Here a three great implementations of Web Fonts using @font-face with surprisingly good browser coverage (i.e. all of them! …if you can get the various font formats).

Google makes things google-easy, but has a relatively limited set of fonts.

Mashable‘s Google Font API Guide.

Font Squirrel has some great free fonts, and code snippets.

Fontspring is a more commercial subscription offering with a wide range of fonts, with demos of how to install.