Stations almost always have little pocket maps of the network for you to take which will help you plan your route.
The other thing you need to know is which ticket to buy. The system works in a number of zones, which are roughly circular centred on central London. The centre is zone 1. QMW is in zone 2. Heathrow is in zone 6. The price of your ticket depends on the number of zones you want to travel through. You will generally need a ticket covering zones 1 and 2, which costs £1.60.
DO NOT BUY A CARNET: these cover only zone 1.
If travelling after 9:30 in the morning (or at weekends), you may wish to buy a one-day Travelcard. These cost £3.50 for zones 1 and 2 (remember to specify this to the ticket clerk), or £4.30 if you want it to cover Heathrow. If you're arriving on Saturday, you can buy a Weekend Travelcard for £5.20, or £6.40 to cover Heathrow. These cover as many trips as you like on all London Underground trains in the zones for which you've bought them, as well as most London Transport buses and suburban trains in the same area.
If you are going to be staying a little longer than the conference, or think you might want to travel a lot during it, you might want to consider a weekly season ticket. These cost £16.60 for zones 1 and 2, and can be extended at a cost of £0.80 a trip to get you to or from Heathrow. They do however have to be accompanied by a London transport ID card for which you will need a passport photo. Finally, there is the London Transport card. This is like a Travelcard except that you can buy it before 9:30 in the morning, and doesn't cover the suburban rail (useless to you anyway). This costs £4.50 a day (break even being a return to QMW and one other trip).
The President HotelIt is at Russell Square tube, on the Piccadilly line. To get to the hotel, exit Russell Square tube onto Bernard St. Turn left at first opportunity onto Herbrand and go straight to Guildford St. The President Hotel is straight on. This is a 3 minute walk. Here is a map of the area.
Guildford St, Russell Square
London WC1N 1DB
+44 0171 837 8844
For further instructions and maps see the College's "How to find us", or the Computer Science Department's How to Get Here page. The former includes a link to a local street map.
Exit Mile End tube, turn left heading east, cross Mile End Road, and continue heading East. You pass Regent's canal and then come to QMW buildings. You pass Arts, and Laws, and eventually come to a building on your right, set back from the road, which looks out of place in that it's older than the others. It has a similar-looking clocktower in front. This is the Queen's building. Right beside Queen's, to the left of the small Parking/drop-off area is the People's palace. MFPS is held in there.
Travel time can vary from 25 to as much as 50 minutes. You should allow 40.