I have finally managed to take the Trie described in my previous post and create a library for anyone to use. You can find it here:
This one is completely overhauled and improved. The trie now implements IDictionary and can be serialized. It now allows any data type to be used as a value (not just class types) and you can even store nulls as values. More importantly, you can now get the strings which start with a particular prefix and not just their associated values. The code also has a comprehensive unit test. See the wiki in the link above for examples on how to use it and download the DLL for your projects.