Is there some tool I'm missing? Only thing I know about is overture, and it has a lot of limitations.
You can just type in a keyword and get how many times it is searched here: http://www.digitalpoint.com/tools/suggestion/
Yep the digitalpoint keywords suggestion tool is the tool i use for my sites when its about looking for what people queries on the internet
Follow this link: http://www.digitalpoint.com/tools/suggestion/ Add a keyword in the field "Phrase", choose your market which is which country. Submit and you are done, you'll see a range of keywords and how many times people queries them, Neat stuff
You may also find it's worth paying the $8.00 or so for a day's use of the full Wordtracker tool. This gives some useful additional functions including finding related keywords either from a thesaurus or from the keyword metatags of top ranking sites, misspelling tools and the top 1000 current and historic searches. Wordtracker subscribers also get results which are 300 keywords deep, which is many more than the free versions provides.