I recently relased the language versioning SimpleText.NET system/utility on CodePlex.
Here the short snip from the project site description:
SimpleText aims at enabling .NET developers to language version sites or apps in a simple manner.
A focal point is servicing external translators with MS Excel export/import.
Texts can be harvested from your source code based on a simple custom format.
Read on at the CodePlex site and take it for a spin. Don't hesitate to drop me a line on mail or the CodePlex discussions if you have comments or suggestions for improvents.