I have an AT&T iPhone unlocked to be used on O2 in the UK. Current firmware version is 1.0.2. The phone was sold to me unlocked off ebay... before I saw all the articles about the 1.1.1 upgrade possibly "bricking" unlocked iPhones.
What I want to know is if there is a way I can upgrade the firmware without "bricking" my iPhone.
Mac Specs: Black Macbook C2D 2GHz 3GB RAM 250GB HD
I would say the 1.02 to 1.1.1 upgrade is worth it simply for the stability fixes and the double tap feature.
To be able to upgrade your iPhone, you'll need to "virginize" it before upgrading. There are plenty of guides available online. I can't link to them as it would be against forum rules, but if you do a Google search you'll easily find them.