We assume that whoever is driving is coming through Sweden (though the close-up maps should be good enough to help you in case you get lost inside of Oslo). You can also get a pretty decent paper map. The address for IFI, where NUCCC 2001 is held, is Gaustadalleen 23.
Note that studded tires have a penalty fee in Oslo. If you see the toll road, it's already kindof late, but it will probably be okay if you stop by an Esso station or something shortly afterwards.
Follow the signs to Oslo. Around Vinterbro, E6 and E18 merge and stick together for 1 km or so. From then, follow E6 and the signs for Ring 3. If you miss that exit, which brings you through a tunnel called Ringnestunnelen, don't despair, but read how to get there anyway.
Follow E6 towards Ryen. 1 km or so before Ryen, you pass a toll road (NOK 13 for regular cars, 26 for trucks and buses). At the Ryen intersection, stay on the main road. Stay on the main road, and you won't get lost -- all the intersections are free of traffic lights, roundabouts and similar nuisances. There is probably around 10 km of driving left along that road, and it changes name to Ring 3 (E6 turns northeast towards Hamar and Trondheim). See also the overview map of E18, E6 and Ring 3, where E6/Ring 3 is on the right.
Assuming that you didn't make the exit after Vinterbro, and that you're still on E18, it's perfectly fine to keep on that road, too. It may be a lot slower during rush hour, though. As with the E6 route, there is a toll road somewhere.
About 1 km from the toll road, you should try to make a right turn off E18 (away from the fjord) and onto route 190 (which may be labeled as E6 with a dotted white line at the edge, since it takes you in that direction). This will get you into a long tunnel, Ekebergtunnelen, followed by a rather brief glimpse of air before you enter Vålerengtunnelen. The second tunnel has a nasty left turn, which is tougher than you may think (though it's worse going the other way). This brings you to an intersection with Ring 3, which you should follow northwest ("left" turn, but you're really making a 270 degree right turn) towards Sinsen/Smestad (Not Ryen, which is completely wrong). This is illustrated at the top of the E18/E6/Ring 3 overview map, and the middle right of the Ring 3 overview map.
If you're on Ring 3 heading west, you can now safely go to the section on driving along Ring 3. If you missed the exit to get through the tunnels, you should make the next exit, route 4. If you fail that one, you'll end up in a steep and slightly twisting tunnel below the fjord, heading westwards, and you don't want that unless you've got a good map.
Route 4 has traffic lights, roundabouts and regular intersections. You'll be driving through central parts of Oslo. Of the two lanes going in your direction, choose the left lane. Here's a description of the road going from the exit off of E18:
You're on a two-lane (in each direction) bridge, with an almost immediate exit on the right that you must not take, followed by a roundabout. Go straight across the roundabout, keeping the left lane. There are several traffic lights. At the end of the street (Vahls gate), the left lane turns left (Jens Bjelkes gate), the right lane turns right. Following the left turn, make an immediate right turn. Follow that road (Sars gate) straight ahead. At the third or fourth traffic light, route 4 takes a slight left turn onto another road (Finnmarksgata). The next intersection (Carl Berner) is largish, with three lanes. A tram line in the rightmost lane and the center lane are route 4 (now Trondheimsveien), heading north to Ring 3, and Ring 2 (alternate route) going left. Keep straight, and eventually, you will see a sign for Ring 3 (the exit is on the right) about when the road turns into a freeway style road. The intersection (Sinsen) with Ring 3 is a large roundabout. Choose the left lane in it, because you're going left (west, towards Smestad). Follow Ring 3 for a few km.
If you chose to make the left turn at Carl Berner, follow the main road straight for a few km. After a while, you will cross another tram line (Vogts gate). After 4 -- four more traffic lights, you will drive uphill for a couple of hundred meters, cross another traffic light, and enter a rather broad road with trees on all sides. On the right side of the road is Ullevål hospital (the grey and green areas above the second red stippled arrow and the Ring 2 sign on the first Ring 2 and 3 overview map). At the second traffic light after this, you will cross yet another tram line (Sognsveien). Keep to the right, and after the slight uphill drive, there is another traffic light where you're going to turn right onto Blindernveien. The following maps show how to drive in that area (there are also some nice red lines showing how to get there from a couple of different angles):
Follow Ring 3 for a while. You will pass one bridge, followed by a tunnel. On the other side of the tunnel, there is a blackish building complex (actually Ullevål football stadium) on the left. Keep in the second lane from the left (middle lane), the right lane will exit. Wait until passing that stadium, and you'll have a high school on your right (Sogn). Get into the right lane, which will exit for Rikshospitalet, Universitetet, an Esso station and McDonald's. On the second overview map, this is invisible (although you can see Sogn), so look at the close-up map of that area instead.
After taking off of Ring 3, you'll end up in a roundabout. Aim for Rikshospitalet, but as soon as you've come up most of the gentle right-turning slope, turn left and cross the tram line. Follow that road (Gaustadalleen). (Jump to the northern IFI map.) Keep straight at the next intersection, and IFI will be on your left side. Make a left between the two buildings on the left, go downhill, go left again, and end up at the gravel parking lot.
The maps are printable, though not of very high quality. If you want a detailed Oslo map in paper, we recommend you stop by a gas station (e.g. Esso) and ask for "Oslo Kartboka 2000" (or 2001, published by "Cappelens kart", red cover with an overview of the areas around Oslo). Unless they have changed their map pages (the 1997 and 2000 editions are identical in choice of those), Ifi (the building NUCCC is borrowing) is on page 35, coordinates D9, at the east side of that square, just north of Forskningsparken. It is important that you at least get the 2000 edition, since the roads have changed around us.