These sites provide tools to help you choose fonts, style text and write the CSS.
Typetester
Lets you compare several fonts side-by-side
http://www.typetester.org/
CSS Typeset
Modify text with sliders, get the CSS to make it happen in the next window. Simpler to use but less to modify than Typetester
http://csstypeset.com/
Flipping Typical
See the fonts on your computer, nice little site
http://flippingtypical.com/
Typechart
Another way to see prospective fonts and get the css
http://www.typechart.com/
HTML Ipsum
Lorem ipsum text generator. Great thing is that it doesn’t just give you paragraphs but gives you HTML with lorem ipsum stuff in it. Including lists, forms, navigation etc.
http://html-ipsum.com/
Photoshop Typography Shortcuts
http://www.viget.com/inspire/seven-typography-shortcuts-for-photoshop/
FFFFallback.com
This lets you see what your site looks like with different fonts so you can choose a fallback font.
Photoshop Dummy Text Tool
http://www.viget.com/inspire/dummy-text-panel-for-photoshop/