zabatonni

Automatically finds duplicate terms (with same name) in each taxonomy, then moves posts from duplicates to its original terms and deletes duplicate terms.
You can choose which duplicates you want to merge and delete.

Merge duplicate terms

Plugin for easy merging duplicate terms (tags, categories, ...)

Aaron Forgue

<a href="http://www.vbpress.com/" rel="nofollow ugc">vBPress</a> is a WordPress plugin that seamlessly integrates WordPress with vBulletin.

vBPress

vBPress seamlessly integrates WordPress with vBulletin

Merge duplicate terms vs vBPress