Mother Boards & Processors

My queation is concerning MB’s and Processors.
which is the best way to tell how fast processor a MB would support?
can it be tell by just looking at it? or do I need the original docummentation/online documentation?.
What do I have focus on whentrying to buy a combo (MB and Processor)what do i have to look for?
I also want to inquire about processor’s soket on MB,
is there a web site where I could get a list of sokets all the different processors there is,
you know Celeron = soket 370 AMD Duron = ?????
PIII = ?????
Athalon = ?????
please be as detailed as possible!
Thanks!