The freely available open source project International Components for Unicode (ICU) has UTF conversion built into it. The latest version may be downloaded from the ICU Project web site. Many other libraries may have built-in converters, so you may not have to write your own. [AF]
All the converters for this job that I found through Google are web apps. I tested several, and the best I found was branah.com/ascii-converter. It will accept input in either ASCII, HEX, Decimal, or Binary formats, and simultaneously produce a conversion to all of the other types.
In this blog post we discussed the Simil algorithm and showed several ways to use it in your applications. The free download includes all DLLs discussed here, as well as the Access 2007 sample application.