Shifting the pitch (and tempo) of music rather than retuning your guitar

If you, like me, enjoy playing on your guitar to music from your PC, you will share my annoyance at the fact that bands often tune up or down a step or so for different songs. While it might be simple enough to tune your guitar up and down as and when necessary, I think that everybody will agree that it's a bit of a pain. Here's a solution for people like me who tend to have, well, an indolent approach to their guitar.

So, since we don't want to bother tuning the guitar to the song, let's look at tuning the song to our guitar! The primary tool for this is Foobar 2000, a player that I can without exaggeration say is the best in the business. While I'm using it on Windows, I believe that it also works without any serious hitches under Wine on Linux. That said, I'm not entirely sure if plug-ins work reliably in that environment. Once you have Foobar2k installed, here are the steps to get pitch and tempo shifting up and running:

1. Our objective can be accomplished by installing a "component" or plug-in. To do this, visit the component page for the foo_dsp_effect and download it via the Download link.
2. The component should now be in a zipped format. Unzip it.
3. Installing it (a lone file named foo_dsp_effect.dll) can be accomplished in two ways: you can either simply copy the file to the components directory within the application's installation directory (customarily at C:\Program Files (x86)\foobar2000\components). Alternatively, you go into FB2K's preferences dialog (File, Preferences) and in the Components tab, click on the Install button and locate the DLL file to install it.
4. Restart the application if necessary.
5. Back in FB2K's Preferences dialog, select the Playback and within it, the DSP Manager tab.
6. There should now be two areas named Active DSPs and Available DSPs. What we now need to do is to move any of the DSPs ("Digital Signal Processor" for the curious) that we want to take effect from the Available to the Active section (or vice versa).
7. In the case of pitch shifting, just double click on the Pitch Shift DSP which should move it to the Active area.
8. Highlight the now active Pitch Shift DSP and click on the Configure selected button on the top.
9. This should bring up an interface where you can increase or decrease the pitch based on semitones (1 semitone = half a step or 1 fret). Changing the value while listening to a song will demonstrate that the shift happens in real time before you've clicked on OK! Change the value to one of your choice and click on OK to save the changes.
10. To remove the shift, just remove the effect from the "Active DSPs" area (and back to "Available DSPs").
11. There are two DSPs which can be used to slow things down and work in the same way as the Pitch Shift DSP. They are named Playback Rate Shift and Tempo Shift respectively. The difference between the two is that the former works similar to a slowed down cassette tape / reel which results in a change in pitch while the latter doesn't have an obviously apparent change in pitch, but does not provide as smooth a playback.
12. To expedite matters, once you have your DSPs set up (you can have more than one), give the preset a name by typing it in the DSP chain presets field at the bottom and clicking on the Save button. To load the preset later, just select it from the drop-down and click on Load.

That should be about it. Hope this helps!