Transcribe by 7th string software is the best for learning and pulling apart a tune. it has a 30 day trial and is reasonably priced. I used to use the amazing slowdowner but transcribe is just so much better.
Transcribe looks great. Thanks for mentioning it. If I were going with a Tascam trainer I would get the GTR1. http://www.amazon.com/Tascam-GTR1-P...8&s=musical-instruments&qid=1284382647&sr=8-6 There are a couple of apps for Ipods and there is always Audacity.
Tascam, Its more portable. Tuner, metronome, and everyting else in the smallest pocket of your gig bag. You don't know how many times my various bands have asked "Does anyone have a tuner with them?"
I just use Quicktime 7. It came with my computer and it works just fine for learning songs. Of course the quality of the slowed down song may not be as good as programs that have that as their primary function but I figure if I have to slow a song down that to the point where the quality really begins to suck I'm probably not ready for it.
Checking out both the MP-BT1 and the GTR1 myself. It appears that the MP-BT1 is for bass only, whereas the GTR1 works with both guitar and bass. Also, the GTR1 has mics for recording and can have up to an 8GB SD card. You can view/print/download manuals for both devices if you do a quick search. I checked out both units on Amazon.com and the GTR1 is only $20 more than the MP-BT1, but seems to offer lots more features. As I also play guitar, I'm leaning towards the GTR1. I am still checking out other options, such as software, so thanks for the suggestions of Transcribe. I'll probably download the trial version and see what I think.