Easy Hash Compare is a free and easy to use app to compare the MD5 hash values of two files on your Android file system. It will allow you to know, with some certainty, that two files are equal.
Simply select two files from the filesystem and voila! MD5 hashes and an automatic comparison.
You can download Easy Hash Compare from the app store here.
Update 4/2012 This is now open source and hosted on GitHub. Check it out at my GitHub page.