This page contains a collection of online tools that I've found in my travels.  Share freely.

HTML Formatter - nicely ident dirty HTML

Line Break Removal - put an entire piece of code on a single line (works well with HTML)

Firebug Lite  - the popular HTML sniffer tool on any browser

Jsdo.it  - edit javascript online, fork, and share

CodeRun - online IDE (C#, Javascript, PHP, Silverlight)

FlipTitle - flips text

JSON Parser - formats JSON data

HTML to PDF - convert web pages to a PDF

CSS/HTML Color Names - nice table with simple names

Person Finder - tools to find people

SQL Joins Chart - a simplistic view of sql joins .

Base64 Decoder - encode/decode base64

Default Password List - a good stop gap

Spreeder - an excellent free speed reading.  Just add bookmarklet to your browser, highlight text and click it.

WriteCodeOnline - write PHP or Javascript and test it on the fly on this site.