I have been asked a couple of times whist at the Alt.net and ReMix conferences about the local user groups around Leeds. Well these are the regular free community events I know about:
Black Marble community events - my company runs free community events at a hotel between Leeds and Bradford roughly monthly from autumn to spring. We invite a variety of leading .NET community speakers.
The Yorkshire Extreme Programming and Agile Methods Club (XPClub) - meets the 2nd Wednesday of the month in the centre of Leeds. This is a group of .NET and Java developers interested in agile development bast practice.
BCS West Yorkshire Branch - the local branch of the BCS meet either in the Leeds or York providing a wide range of IT related sessions (they also have links to the events run by the local Institution of Engineering and Technology branches)
Leeds branch of SQL Server User Group - the local branch of the national SQL User groups. As the name suggests is targeted at SQL users.
Geek Up - run monthly events cross the north of England targeted at web designers and web developers (I have not been to this group, but members of the XPClub have and say they enjoyed it)
Vbug - run some events in Leeds, but I think these are organised by the Manchester branch
Now there my be others that I don't know about, if you know of one please let me know.