Go to California Micro Device's page
www.calmicro.com/products/telecom_micro.htmlThe datasheets there take a long time to download because they're scanned from paper ones, but the info is there for their 65c02, '21, '22, '51, '150, '151, and maybe others I'm forgetting. Western Design Center's site,
www.westerndesigncenter.com also has data for their 65-family products.
www.6502.org has data sheets of other ones as well, including many that are no longer in production.
On the dusty book shelves of some non-chain electronics stores, you may still find books like McGraw-Hill's "CRT Controller Handbook" which covers the 6545 and others along with a lot of explanation you may not find in the datasheets, or Howard W. Sam's "Advanced 6502 Interfacing". 6502.org also has a book listing.
In this 6502 Delphi forum, check out the "Tip of the Day" subject from a year ago for ideas for using the '51 and '22. I found a small difference in the Rockwell and CMD 65c22's, and all brands of 6522 or 65c22 have a bug in one of the 7 serial port operation modes. (There is a way to get around the bug.) I discuss both of these and lots more in the "Tip of the Day" column.
Garth