On May 10, Google Labs released Google Trends, a simple to use tool that provides keyword or keyphrase comparisons. This can be very useful in determining the best keywords and phrases to target with your PPC campaigns. Just enter two keywords or phrases separated by a comma and Trends will spit out a nice chart and bar graph showing you the search popularity of the terms entered, broken down by cities, regions and languages. While this is certainly not a tool to replace WordTracker or the Overture Keyword Selector Tool, it is a nice service that can augment your research.

By the way, DigitalPoint offers a tool that combines the results of both WordTracker and the Overture KST; check it out here.

Both of these handy tools have been added to the Free Tools links in the left sidebar for your easy reference.