I have used overture keyword inventory and seobook's keyword suggestion tool in the past but there was always some stuff I wish I had more from them. I finally found the time to create something that would fit my own needs. Using as a guide the very nice clsOvertureSuggest.php class from the seobook's keyword tool (which uses the yahoo overture database) I managed to create a keyword tool that would keep up to 25 queries on the page and then at the click of a button it would add up all the relevant searches to a grand total of searches.
So without further ado here the search engine queries estimates tool, its in an experimental state but very useable (and usefull if I may add)
Using it is very simple just type the query you are interested in and all the relevant queries would appear. Doing more term searches does not discard your previous searches (the 25 last searhed terms are returned). Clicking on the queries that one thinks are actually relevant would add them to the grand total.
The tool probably needs some improvements and I do welcome any suggestions or feedback. I also welcome the help of any other developer interested in improving this further. I do have some ideas on improvements but I have to find the time between projects and family to put them to work so if anybody is interested in helping out please don't hesitate to post here.