If your into the technical aspects of cars i'm sure you would enjoy reading these sites.
http://www.autozine.org/technical_school/tech_index.htm
http://www.f1technical.net/topic2.html
http://www.chris-longhurst.com/carbibles/index.html
And of course i'm sure all of you knew about this site already but www.auto.HowStuffWorks.com is great too.
If you know of any other good technical sites about cars than please share them.