You can hire a freelancer try Elance http://www.elance.com
Or you might check the licensing to see if you can modify logos that are ready made. Search existing logo sites to find a base logo. (As I said read their licensing agreement to see if this is allowed).
Here are some to try -
Logo Search - http://www.logo-search.com
LogoMaid - http://www.logomaid.com
Web Design Elements - http://www.webdesign-elements.com
Here is a good summary of What to Look for in a Logo - http://www.developer-resource.com/what-to-look-for-in-logo.htm
This is a more in depth article -
What Makes a Good Logo - http://www.logo-search.com/what-makes-good-logo.htm
And Building an Image with a Logo - http://www.logo-search.com/building-an-image.htm
Bring Your Product to Life with Personality - http://www.logo-search.com/bring-your-product-to-life.htm