Great :!: A volunteer :)
Did you read
NHibernate Needs You! ? ;)
If you really want to start helping, check out the CVS version and look around...
Formatting the code is certainly a TODO in NHibernate, but ATM, I worry more about fixing bugs and adding new features; so when you start feeling confortable with NHibernate source code, try to fix some bugs and post the patch on
Jira bug tracker. It will also give you a deeper understanding of how NHibernate works.
We will think more about Formatting when we get near the 1.0 release :)