There have been no official words yet - but all suggestions point to yes! The game was hugely successful and the developer (gearbox) was quoted saying "Everyone here loves the franchise, and it seems like the public is really coming back with praise and love. So yeah, if everything makes sense, Borderlands 2 seems like a no-brainer to me."

Also, in a twist, it sounds like, although most other games go with numbered naming schemes (what are we on now, Final Fantasy 14? God of War 3? etc), the name "Borderworlds" has been trademarked by Gearbox. There is speculation that the action may be taken in to space, other planets, etc. No final word yet, but it's early, and when there is this much talk on the street, it's often right.

There is also suggestions that Borderlands will become a key franchise, marketed more heavily in the future due to it's success.

I loved Borderlands too - I fell in love with it instantly! I didn't like FPS before borderlands but now I LOVE them! I also love the art style, and I really think it helped ease me, as a newer gamer, from childish games like Legends of Zelda and Super Mario into more mature gaming. The only thing I was a little disappointed in was the ending - though I've heard the DLCs expand on that. I have the DLCs, but I haven't played them yet.

I'm just starting my second playthrough and I hit level 40 over the weekend. I play as the Siren, of course!

http://scrambledpixel.com/wp-content/uploads/2009/11/borderlands-character-trailer.jpg

Favorite moment from the game? (alright, one of many)

http://i29.tinypic.com/fmng5x.jpg

As girlieq said there is no official date as of yet, as far as DLC goes I don't if you've heard but the 4th one has been announced and will be about Claptrap Interplanetary Ninja. Here's more info:

http://news.teamxbox.com/xbox/22909/Borderlands-AddOn-Pack-Claptraps-New-Robot-Revolution/