Hi,
You cannot import a mix created with trakAxPC into Garageband. However, you can export your mix from trakAxPC to a format like MP3 etc. and then import it into Garageband.
However, you can use trakAxPC to create a Podcast.
Firstly create your podcast with whatever recordings etc. you want it to contain.
Then Export the mix to MP3.
You have to then upload the MP3 file to the Web and associate this file with a piece of xml code, known as an RSS feed. This code enables specially designed software to locate and track new versions or episodes of a particular podcast and therefore keep the user up to date.
I have attached a few links that may help with creating the RSS feed:
http://radio.about.com/od/podcastin1/a/aa030805a_3.htm
http://computer.howstuffworks.com/how-to-podcast3.htm
http://windowsdevcenter.com/pub/a/windows/2005/04/05/create_podcasts_with_pc.html
If you use Wordpress as your blog, Podcasting is supported as of Wordpress 1.5. Just link to an audio file in one of your posts and WordPress will automatically add the necessary enclosure tag to your RSS2 feed to make it useable as a podcast.
I hope this helps and please let me know if you need any further information.
Many thanks,
Catriona