The new DLC is now available in case you've missed it.

If you bought Borderlands through Steam, you can get the DLC here :

http://store.steampowered.com/app/8990/

Otherwise you can get it from Gearbox, here :

https://store.gearboxsoftware.com/

There's an interesting character build guide over at IGN.

If you aren't sure about what sort of character you want to build, and how to level up, then this will give you some help :

http://uk.faqs.ign.com/articles/103/1038491p1.html

Hey all, just to let everyone know that in order to play Borderlands in Co-Op, you will need to make sure that you have forwarded your ports correctly. Both for TCP and UDP.

If not then you will timeout when you try and join a game, and won't be able to host a game either.

Here's a couple of links for the forwarding :

http://www.gamefaqs.com/boards/genmessage.php?board=942811&topic=51965937

http://img44.imageshack.us/img44/9561/14056834.jpg