This, that or that camera?

So i need a camera expert to give me some advice. I'm going to buy a DSLR camera and i look at 3 brands. Canon, Nikon and Sony.
1) EOS Rebel T1i EF-S 18-55mm IS Kit from canon
2) Nikon D3100
3) Sony α33 DSLR Model (No.SLT-A33L)
The main reason that i'm buying camera is that i want to professionally document my projects. Also, I travel and take pictures.So, which one should i get?

You will have trouble finding an "expert" to help you choose between three different systems, as people will invariably recommend whatever system they are using themselves.
I would say that all three are good cameras, priced similarly and with the same focal lengths for the kit lenses (18-55). If possible you should really go to the store and try them out, see how each feels in your hands, how you like the viewfinder, etc.