Originally posted by Stormin' Norman:
Here is Patrick Sun's website on his Sonotubes. He is that master at them and has very detailed instructions with pictures of all his projects. These are for large home theater subs, but you can just scale it down. 
Sonosubs Patricks site is pretty good. There is another site from one of the owners of SVS that is pretty comprehensive as well. Don't have the link handy though.
