A useful tool to get a rough estimate for how many times a keyword gets searched on google a month.

http://www.technobloggie.com/googleSearchEstimates.php
I don’t know how accurate it is but it might provide you with another reference point to contrast with overture search counts.
The same guy offers some other tools as well:
http://www.technobloggie.com/password-protected-rss.php - How to password protect your [...]

With RSSmix you can combine any number of RSS feeds in one new unique feed. It’s a very useful tool if you want to publish feeds.
I used it on a page where I wanted to publish a related feed but I only found 4-5 feeds that weren’t updated too often. With RSSmix I got all [...]

I have stumbled upon two free cloaking scripts. You might want to give them a try before buying a more serious and expensice cloaking tool. I haven’t used them personally so I don’t know how good they are, but if you give them a spin don’t forget to leave a comment here. See? You don’t [...]

Search Engine Cloaker is a pretty good cloaking tool. I have seen it being used with great success and the creators claim that they only know two cases of sites being deindexed after using it. I don’t know if that’s totally true but I haven’t seen any complaints of de-indexing in their forum.
It uses an [...]

Some lists with the current most popular search queries:
http://buzz.yahoo.com/
http://www.google.com/press/zeitgeist.html
http://50.lycos.com/
http://www.search.com/top
http://www.metaeureka.com/voayer.shtml