As indicated on the playstation blog:

"Finally, for all you lucky North Americans that were accepted into the Online Water Beta and eagerly waiting for your invite….check your mailbox early next week, we had to settle a few technical issues, but its sorted out and we can’t wait for your participation."

http://blog.us.playstation.com/2009/09/littlebigplanet-sack-it-to-me-the-lots-of-videos-corrections-and-free-dlc-edition/

Question. Are there plans to involve some sort of simplistic combat system in the game? I've yet to see any levels that involve enemies and you having to dispose of them in any way.

^^
There's lot's of levels like that, using either the MGS paintgun (which works best) or built in editor enemies and editor created 'weapons'

My kids seem to be pretty good at finding combat levels anyway.

Oh ok. I've seen a lot of videos but they've all been about dodging traps and using physics to get past obstacles. I was hoping for the ability to create some more traditional levels. Happy to know you can.

Yeah, the paint gun allows for combat, and quite a few people have built tanks, etc. so you can even have vehicle combat!

I wouldn't ever claim LBP lends itself to anything other than a particularly cute form of combat, but it is there.