So you know how plus owners get free stuff every month? Well I have noticed that on tuesdays there are some free things in there not mentioned on the updated. Right now some of the MAG avatars are free, was this already mentioned? I swear I didn't see anything about this.

It was mentioned in the update.

http://blog.us.playstation.com/2010/07/06/playstation-store-update-146/

thanks, hope they do this every week...might get a full year

last week it was qore, it seems they are adding more stuff every week. I love it :)

If I subsrice to PSN for three months, once those 3 months are up can I still play/use the content such as LBP or free avatars i got from PSN ?

there is a couple things that you will own...but almost all of the "free" content is essentially rented to you for the duration of your subscription, so once it ends you can no longer use it.