Firstly, this is a forum - if you want to edit/add to what you said shortly after saying it then please use the edit button rather than double posting.
Secondly, the user bars are there for people to use (that's what a signature is for) but hotlinking them (i.e. copying and pasting the URL from someone else's site and using it on another site for your own purposes) uses up the bandwidth of the original site. As far as I'm aware then Hangar-8's user bars were made for people to use, but you need to host it yourself (e.g. ImageShack or similar).
Back on topic...I didn't realise Hangar-8 had closed registration, but I just tried and it seems he has.
Making a badge is no different than making any other kind of image. TGA is just a file format, and most reasonable editors support it (i.e. Paintshop Pro, Photoshop, The Gimp, etc). I've got a
basic badge-making tutorial on Skins@HWT. All that you need to do to make it a .tga is to pick "Targa image" (or whatever the app calls it) when you save it, make sure that it is uncompressed and the full 32-bit colour depth. If it comes out at about 16KB then you did it right. If it is significantly smaller then you need to try saving it again with some different settings.
Hope that helps.