One of the sites that I visit regularly is ilovetypography.com. A quick glance upon getting to the homepage reveals the sheer amount of information available on this site. Aside from the free desktop wallpapers and stuff you can buy, there is always good reading within a click or two.
The list of popular articles on the center column showcases some of the best resources they offer. Currently on this list are articles on how to make a font, type terminology, type history, a web typography guide, choosing type, and identifying a font.
Web design benefits greatly from good use of typography. The same rules that have applied to print for centuries are critical in web design and have been largely ignored since the web exploded into what it is today. The viewers have the same basic need for clarity when accessing information–regardless of where it is displayed. I was very glad when I first learned about this site. The time invested in learning how to improve web typography pays off in the quality of the design as a whole.