Well last year at Southampton, they sent out a heap of information including freshers packs in the first couple of weeks of September. They gave you details of how to book tickets online etc.
The only problem was that the packs didn't get to everyone and a lot of people missed out on freshers week tickets - a lot of angry students.
And yeah it's a lot of fun, assuming you get on okay with the people you meet in the first few days, otherwise it can be a bit difficult (one of my friends struggled for the first few weeks because her flat mates didn't ever go out). I thought it was all pretty cool, lots of fun. I was really unwell though so I probably didn't maximise enjoyment (illness was why I dropped out).
The only negative thing about freshers week - it makes getting down to work such a shock to the system and you've got hangovers to recover from
How are you feeling?