YouTube
I use YouTube in several ways for rehearsal. The first is making song lists so that I can familiarize myself with the songs that I will be playing. I won't go into the details of how to do that, but whether you use a computer or a mobile device, you can easily build a playlist of songs.Sometimes the song leader will provide a MP3 rehearsal track. While this is useful in itself, I like to have all of my songs in a YouTube playlist so that I can listen through the entire set list in my car. It's also helpful when I'm practicing if I have a continuous playlist instead of jumping back and forth between YouTube and an MP3 player. So that brings me to my first tool: TunesToTube.
TunesToTube
TunesToTube allows you to upload an MP3 file to your YouTube account as video. You can either select a static image from your computer or let it generate a generic background for your video. Whenever I upload a video like this, I always set the privacy set in YouTube to private since this video is only for my rehearsal purposes.YouTube MP3convert2mp3.next
Sometimes I need to go the opposite direction and take a song from YouTube and download it to my PC. For that I use Audacity
I love Audacity. It is "a free, open source, cross-platform software for recording and editing sounds". It is useful in many ways, but for this discussion, I want to talk about the transpose feature. Often the key of the song that the original artist recorded the song in is not the same key we will be performing in it. Sometimes I will practice the song in the key of the recording just to familiarize myself with the song. But I like to practice the song in the key that I will be playing it. That's where Audacity comes in.To transpose a song in Audacity, first open the song using File -> Open.
(Keyboard shortcuts: Ctrl+O in Windows and ⌘+O on Mac)
Next select the entire wave form using Edit -> Select -> All. (Keyboard shortcuts: Ctrl+A in Windows and ⌘+A on Mac)
Then select Effect -> Change Pitch from the menu:
Then choose the key you are transposing from and the key you want to transpose to and click OK:
You can then save it as an MP3 file by going to File -> Export as MP3. (Note that before you do this for the first time, you will need to install an additional dependency called the "LAME MP3 Encoder". Instructions can be found here.
* Updated 5/20/17: YouTubeMP3 no longer works for me. convertmp3.net seems to work better anyway.