How do I use mobile blogging on AT&T?

I very recently purchased a Sony Ericsson w580i Walkman phone from AT&T. I mainly got it for the music features, but soon realized that it had a lot of camera features, one of which being mobile blogging. I take a lot of pictures, and do a lot of blogging, so I thought this would be a great feature. I went to Sony Ericsson's website and followed the instructions, but my phone is set up differently than the phones in their examples. How do I use mobile blogging on my phone? Do I need a data plan, or can I use MMS instead?

Thanks!!!

P.S. One of my keys cracked, also. The phone is under warranty still. Will AT&T give me a new phone, or ship me a refurbished one?

Thanks again!