Can you unlock a passcode protected iPhone without the code?

I got my iPhone stolen but I had it passcode locked. I was wondering if it is possible for someone to get through it and see all of my information.

Of course I called my cell phone provider and had them cut the phone off but what about all my pictures and messages?

If they have the skill anything is possible. They will probably just wipe out the drive and resell it or use it via wi-fi or as an MP3 player.