There are a few great sites out there in which to pick up stuff for your blackberry whether it's free or not.
These are three awesome sites which should give you some direction.
Also, don't forget to download google maps(free) www.google.com/gmm
and opera mini 4.0(also free) www.opera.com
If you have any questions just repost
I just got a Pearl (the original one) for Christmas and am loving it so far. I was just wondering if anyone could point me to a good, legitimate resource site for things like themes, apps etc. I've found some themes but they all cost money - I'd just rather try out some free ones first.