British Airways and BMI have regular flights from London Heathrow and other UK destinations to Glasgow Airport - these are often well priced from London, but can be expensive. Heathrow is also an extremely large airport which means a lot of walking and congestion in the air - give plenty of times for changeovers - it may take your flight a while to land and you will probably have a long walk in the terminal. Amsterdam can also be used for connections to Glasgow - with regular flights by KLM and EasyJet.

London's Luton and Stansted airports provide regular low-cost services to Glasgow/Prestwick operated by EasyJet or Ryanair.

As well as flights from many UK airports (e.g. by BA, BMI, EasyJet, and Ryanair) there are at regular direct flights from/to:

 Rail to Glasgow

Timetable enquiries at National Rail Enquiries. In Scotland, ScotRail operates most services and the sleepers to London, with Virgin and GNER doing most day-time services to England. The journey from London is about 5 hours 30.

 Accommodation

Glasgow has dozens of hotels to suit every price range. The tourist information website also has extensive details on accommodation and attractions/events around Glasgow - too many to list individually here.
The SECC Accomodation page lists more.