JDBC drivers

H-

I'm looking to get the jdbc drivers for postgres 6.5.3 so I can hook them up with
JSP/Tomcat.

I found a page that has drivers but not for my version.
Does it matter that they aren't the same?

Any one have a favorite page where I could go and get some drivers for postgres
6.5.3?
If I upgrade to 7.0 will it destroy my existing databases?
Has anyone had any experience with upgrading to the lastest postgres, and if so how
was it? Painful, Pleasant?

Thanks for any information you can provide.
-Sterling