Can Nikkor and Tamron lenses work on a Canon?

I have a Nikon D3000 and I'm thinking about switching to a Canon EOS Rebel t2i. I have mostly Nikkor and Tamron lenses, i was just wondering if they are compatible with a Canon body.

Actually, it would be pointless to switch now. You'd be better off buying a D5100 body.
And no, they use different lens mounts.

No, they don't.

If your camera body is worn out, look at something from the same manufacturer.

More modern DSLRs offer an increase in MP (barely noticeable) Live View and video capability (neither is worth bothering about and people are always complaining about the lack of AF in video mode).

Changing systems is stupid, and there's no reason whatsoever to dispose of a working DSLR unless the, 'Upgrade,' is worth it - it seldom is.

No. Either jump ship entirely and sell all your lenses with the camera or stick it out with what you already have. I'm assuming you are fed up with your camera.

Don't despair. It is worth noting that the D3000 is the worst one Nikon has brought out so there's still hope. Simply sell the camera (only) and get the newer D3200 (body only). Even the D3100 will be significantly better.