Pay-Per-Click Campaign Management Tools

What's the best one to use?

[Kantro]

I have been managing Pay-Per-Click campaigns across multiple SE's, and as of late the pure volume of keywords has made it very difficult to optimize manually.

I am looking for a good Pay-Per-Click Campaign Management Tool/Software Application that can help make my job easier.

Can anyone recommend some good software that is relatively simple to learn/operate but can help with campaign management across multiple Search Engines?

-Thanks,
Kantro