Best sites to track planes by registartion?

[markCSC]

hello

I wonder if you guys could help me in a bit of spying?

I'm trying to keep tabs of where our competition are flying. I've managed to find a few pictures of the planes but nothing recent.

First one is this
http://www.airliners.net/photo/Fugro-Airborne-Surv...

Second is this

http://www.airliners.net/photo/Fugro-Airborne-Surv...

And lastly this

http://www.airliners.net/photo/Cessna-208B-Grand/1...

Any idea of international spotters sites (don't need pics just info on where they are) would be great.

Thanks

Mark

PS yes I know the title is spelt wrong

[motomk]

See a lot of their aircraft in Oz , but don't recognise any of those three.