Utilities
Unicode and HTML character utilities.
HTML Special Characters
Unicode Lookup
Lorem Ipsum
HTML Entities
Useful Links
The Unicode Consortium is of course the definitive reference for all things unicodey.
If you want to display characters outside the Basic Multilingual Plane, you’ll probably need some more fonts. If you have Windows Vista you already have Cambria Math . Cardo, free for non-commercial use, is nice—it’s based on Bembo—and has a fair bit of coverage. Code2001 has a lot of plane 1 coverage, and the DejaVu fonts have some.
Alan Wood’s Unicode Resources contain all sorts of good stuff.