Joined: 13 Jun 06
07 Dec 11 10:55 pm
I use the paid version of keyword spy, though you may wish to just use it for one month then cancel, I think the investment for one month in order to help with your planning is invaluable.
Alternatively, you can use Traffic Travis, the only difference is that with traffic travis you need to input all the keywords that you are spying on. So you might use the traffic travis keyword research tool to uncover 2000+ keywords related to your niche, then after that you can use the tool to see what competitors are bidding on what keywords etc. You can see all the keywords your competitors are bidding on, and can track them over time to see if they are still advertising on them weeks, months later etc.
Hope that helps!