Does what it says!

The plugin does what it says – EASY 301 redirects, emphasis on easy.

I used it on a site that was moving from a homegrown CMS to WordPress so all of the URLs were changing. We needed something to handle several thousand 301s. This plugin not only handled all of them perfectly, it was simple to set up. We used the CSV import process. I had my doubts about the import crashing with that many records in the import, but it handled them without any trouble at all.