My Daily Tech RECOMMENDED APPLICATIONS!
If you are looking to convert an AVCHD movie to another format so that you can use it in your project, then you should definitely check out a piece of software called TMPGEnc 4.0 XPress.
It accepts AVCHD and just about any video format as an input, so that you can convert it to the most popular video formats. Unfortunately it doesn’t support AVCHD as an output.
There ARE free ways of doing this too, I should mention that a free program called Avidemux that can do this too, so if you are technically inclined (Avidemux is harder to use) you may want to go that way instead of spending money on TMPGEnc (but of course TMPGEnc supports more formats etc).
Also, if you are looking for video editing software that is simple and support AVCHD input and output, check out Sony Vegas 9.0. It is excellent and it supports many plugins and addons that make it really expandable. It also has an amazing feature that makes recompression not necessary on certain AVCHD files (ones that you don’t edit), and that really speeds up the time that it takes to render videos.