Learn how to do the basics of lip sync for animation without paying for a sound program. Just watch the video above to learn how it's done. The free program which works on PC's and Macs is JLipSync that you can find here:
The program JLipSync requires that you have JAVA installed on your computer. Download the proper JAVA package for free here:
To record your own voice to use in your animations, use the free program called Audacity from this link:
Just remember to record in 8 bit mono with 1 channel or it won't open in JLipSync.
UPDATE: For those looking for a more robust program which allows the importation of .MP3 files and others, check out Lip Sync Pro. A new program released by Stop Motion Pro that you can read more about here.