Here is an open source project that provides support for 7-zip in your VB6 projects.
Using VszLib.dll + 7z.dll your applications can create and extract 7z, zip, tar.gz, tar.bz2 and many more compression formats. Latest versions of 7z format include LZMA2 method for faster multi-core compression.
Post your comments and questions here.
p.s. @Moderators: Please remove original thread.