I get asked about how/ where to start with pay-per-click campaigns. So here are a few resources to help you:

Visit http://www.payperclickguru.com/ in order to review and compare different pay-per-click search engines. They offer an easy-to-read comparision chart so you can quickly review features of various pay-per-click resources:

http://www.payperclickguru.com/chart.html

This site also is a good place to acquaint yourself with various pay-per-click terminology:

http://www.payperclickguru.com/glossary.html

Once your campaigns start yielding results, be sure to use some comparison websites to find the best pricing for the clicks you are purchasing.

Save this step for AFTER you determine which keywords yield the best traffic.

http://www.compareyourclicks.com/ -
Good website to compare CPC (cost per click)

http://www.payperclickanalyst.com/-
Another good website to compare CPC (cost per click)