Transcribe with Audacity (free!)

To slow down a song so you can transcribe it more easily, you'll need a digital copy of it (WAV or MP3). Then, use the free Audacity audio editor to alter the tempo without changing the pitch.

1. Download Audacity (http://audacity.sourceforge.net/) for your computer (Mac, Linux, Windows) and install it, following the instructions included with the installation.
2. Run Audacity
3. Select File > Import > Audio ...
4. Select the file of the song you want to transcribe.
5. The song's waveform will appear in Audacity's editor window.
6. Select Effect > Change Tempo... (do not select Change Speed..., as this will also alter the pitch)
7. Using the slider or the Percent Change: field, enter the percentage change you want. Note: to slow down the song, enter a negative value (to slow the speed to half speed, for example, enter -50)
8. Click [OK] to apply your settings.

To hear the results and to play along, use the playback controls in the upper left corner of the Audacity editor window.

More Info

Audacity Wiki: Change Speed