The best way in is probably by train - here's a picture of Cambridge station. From London you can choose to go from either King's Cross or Liverpool Street stations; both sets of services are run by the train company WAGN. There is a cheapish and frequent bus service from London, too, but it can be very slow (about 2 hours - it's normally under an hour by train)...
The train station is more than a mile from the city centre, regular trains to London, Ely, Peterbrough, Norwich, Kings Lyn, and Stanstead Airport. etc. There are 3 bus services that go to city. The bus station for local towns like Ely and Newmarket is in city centre in Drummer Street. There is a Park and Ride bus service in Cambridge.
There is a fast and frequent rail service from London King’s Cross & London Liverpool Street through to Cambridge.
There are excellent connections from Scotland & the North via Peterborough, and regional services from Birmingham & the Midlands, East Anglia & the Northwest.
By all accounts when the Eastern Counties Railway company proposed siting a station here in Cambridge there was a knee-jerk reaction from the colleges, fearing that their impressionable young charges would find that the ease of communication to London, and its possible corruptive influences, would divert their minds from the seriousness of academia.
And so the station was eventually built a mile and half out of town - HA! As if there wasn't enough "corruptive influences" in the town itself - why is "Honey Hill" so called? Especially seeing its not even a hill!!!
Anyway in modern times the station is about 10 mins by bike or bus and the trains to London about every 20 mins and so the world is your proverbial oyster (card)!
The train ride from London's King's Cross station takes about 45 minutes to an hour, seats on our train were not pre reserved and with the tickets Jo had, we were able to board any train in both directions. Should you not have a friend in London helping you get a discount, it looks like the cheapest train fare is the L13 cheap day return from Liverpool Station that takes slightly longer and has restrictions on the time you can leave and return. But it appears that you can get this fare at the station, no prebooking necessary.
Cambridge is simple enough to get to from London as there is a direct route from London's Kings Cross station.
The train journey ranges from 45 mins, for a fast train, to 1 hr 30 for a slow. Fare as at 16/11/05 was £17 for a cheap day return.
There´s not direct trains from Swindon to Cambridge. We went to London Paddington and took the tube to King Cross where we took the train to Cambridge.
Don´t remember the price ticket.
For more information click on the web.
Due to the inherent snobbery of Cambridge University the railway station is a good country mile from the center of town.
There is nothing wrong with the walk, as there is a complete absence of hills, but the very regular bus service may be a good option.
Regular trains to London, Stansted airport, Norwich and the Midlands via Peterborough.
P.S Another completly useless fact for you : I seem to remeber that Cambridge Station has an entry in the Guiness book of records for the longest plaform in the UK. Oh dear, I better had go and get my bobble hat after saying that.
From London to Cambridge by national rail:
1. Don't forget to aks for group tickets- 3 or 4 people for 2 tickets if you are travelling in a group of 3-4 persons. It will save you 16.5- 33 pounds which will be used to have a good lunch.
2. start and end your trip from the King's cross station, not the liverpool street station. It will save your time.
3. on the train back, some freshments will be sold, but the cappuccino is no good I have to say.
If you are arriving in Stansted Airport, it is very easy to get the train to Cambridge. Just head downstairs to the station. The trains run every hour and take approximately 1/2 hour to get to Cambridge.
From London, take the train from either King's Cross or Liverpool Street. Cambridge station, shown in the pciture, is about 10-15 minutes walk from the city centre.