What is a good SERP checker
 

Based on different areas in the US?

I go to the website.

Put in the keyword and it gives me the SERPS based on different locations?

GFY.com ....

write your own script ;)

Well usually i use www.seoserp.com to check positions at various datacenters/search engines,but for executing from you own server it would be best to write your own script.

hit me on icq if you need one..