Is this a professional camera?

1) Is the Canon 600D a professional camera?
2) Which is better, the Canon 600D or the Nikon D5100 for entry level professional photography?

Professional cameras cost between $ 4, 000 and $ 43, 000. Professional Canon cameras are the 1D series. The 600D is an entry level DSLR.

The canon 600D is amazing i'm gonna get it next week
its a great cam for beginners: D

Both the 600D/T3i and the D5100 are entry level cameras. A "professional" grade camera starts at around $4, 000 for the body only.
DSLR cameras come in three grades:
entry level (consumer) $550 to $1, 000
Semi-professional $1, 000 to $3, 000
Professional $4, 000 to $45, 000+ (Body only)
Both Canon and Nikon make nice cameras. The best thing to do is visit an actual camera shop (not bestbuy/walmart) and try the different models within your budget to see which feels the best to you. I bought a Canon for its ergonomics/feel/menu and control layout and a fellow photog chose Nikon for the same reason… It is about personal preference.
The one thing to remember is to budget in extra money to cover an extra battery, memory cards, camera case, a USB memory card reader, and taxes (these can add another $200-$250 to the camera price).
Also, most camera shops offer free beginner camera/photography classes (and free prints) when you buy a camera there.
Either of those two cameras are nice. My thoughts on photography/cameras…
1) Photography is roughly 70% photographer skill/experience, 20% lens quality, and 10% camera body
2) I would rather have a $600 camera with a $1, 500 lens than I would a $1, 800 camera and a $300 lens

No.
You can produce professional grade images with the 600D but it is not really rugged enough to be considered a professional class camera.
In a professional grade miniature format camera, look for weatherproofing, extremely fast AF lock, very low image noise, metal internal chassis and high shutter activation rating. Think Nikon D3s, Nikon D700, Canon 7D, Canon EOS-1D Mark IV.

It isn't the looks or price that determine if a camera is professional or not, it's the person using it that determines that.

Neither of those cameras are suitable for professional photography.
They are both entry level cameras designed for hobbiests, and will not withstand the rigors of professional use.
The Canon 7D was designed for entry level professional photographers.

Both the 600D and the D5100 are consumer grade DSLRs.
They are cheaply made, have small buffer slow shots per second, cheap plastic bodies, non weather sealed casings and a cropped senor.
Does that mean they are horrible cameras? No… It just means they weren't designed with the photography professional in mind but for the advanced amateur.
In Canon, the 7D is the current lowest camera considered made for professionals, I don't know Nikon well enough to say what their first "pro grade" camera is.
Either one of these cameras (600D or D5100) will work fine for you as your first DSLR.

No it is not a professional grade camera. Canon's lowest pro grade camera is the 7D while Nikon's is the D300s. The T3i and the D5100 are second tier entry level cameras. While the 60D and the D7000 are one step above that. If after all of these people telling you otherwise, you still think the camera makes the pro, perhaps you should look for another profession…