You've just inherited the webmaster position but know little about the day-to-day operation of a website. What books or online resources should you look at to learn more about being a webmaster?
Here's my hitlist...
Sitepoint is probably the closest online resource to what you're looking for.
AListApart is geared more toward style and best practices but it also has a lot of articles about general website management, bleeding edge web technologies, and how to prepare for them.
This site... Obligatory.
The last two aren't specifically geared toward webmasters but, if your webmaster position has anything to do with writing/modifying code on the site you'll wish you had them.
While technically a site for Web Devs & Designers they keep things at a high level making for a very good resource for keeping up with technology trends and style.