TheDowser - Overture Keyword Tool, Google Keyword Sandbox, Keyword Harvester, Google AdWords report analyzer, Google AdWords optimization tool, log file analyzer, conversion tracking and optimization tool.
http://www.thedowser.com

WordTracker - Wordtracker helps you choose the right internet marketing keywords that will help your search engine placement and ranking. Use Wordtracker for keyword research. Web marketing is all about search engine ranking, and that starts with the proper internet marketing keywords. Get a free keyword report and web site promotion information!
http://www.wordtracker.com

Keyword Suggestion Tools - A handy little tool will show you the results of your query from both Wordtracker and Overture for determining which phrases are searched most often. Enter a search phrase below to see how often it’s searched for, as well as get suggestions for alternate (but similar) keywords.
http://www.digitalpoint.com/tools/suggestion/

Keyword Ranking Tool - This utility can be used to check search engines for keyword ranking and track search engine ranking for your various keywords over time, which, as you probably know, is critical when doing search engine optimization.
http://www.digitalpoint.com/tools/keywords/

Overture Keyword Tool - After entering a keyword or phrase, Overture provides a list of related phrases that have been searched on. The tool provides a count that indicates the number of times the phrase has been searched on http://inventory.overture.com

Topword Tool - Topword Tool is a free online tool that analyzes a complete web page and counts keyword occurrences, as well as keyword phrases (number in brackets), equal to or above that set in the Minimum Occurrences setting. It supplies a list of keywords and keyword phrases which are most likely to achieve the highest rankings on a major search engine. The tool will also analyze your meta description/keyword and title tags and then, through color coding, inform you of words/phrases which should be included. The main use for this tool is checking your optimization and tweaking existing web sites to rank well.
http://www.abakus-internet-marketing.de/tools/topword.html