I have the 1.0.2 software and want to download new applications and games but dont want my iPhone to brick, even though you can re-unlock them. Can I do it?
Depends. It will very on the version of firmware the program was written for and the version you have.
There is a cat and mouse game going on with apple. I'd say go for it but don't download any firmware unless the iphone dev team has unbroken the updates.