This is a good example of why to check with the Better Business Bureau - even for finding a tax preparer.
Here are the tips I found for choosing a good tax preparer - they come straight from the IRS.
Here's a link to their page that offers even more advice. http://www.irs.gov/individuals/article/0,,id=133088,00.html
The IRS also offers help if you choose to file your returns yourself....
Click for help: