Edit: This instructable is a bit of a work in progress, so any suggestions you have to improve it will be greatly appreciated. Also, I apologize that the screenshots are hard to read, I thought they would be bigger
Step 1: Materials
-Computer running Windows XP or later
-Itunes (version 10)
-Iphone transfer cable
-Audio files to make into ringtones, m4a is easiest, but pretty much any file can be converted
-VLC (Optional)-It can be downloaded freely here: http://www.videolan.org/vlc/
-Connection to the internet (preferable)
-Itunes account (optional, I think)
Step 2: First: Select Your Audio File
Just right click on the background and select "Save As", and save it right to your desktop
Alternatively, just download it straight from here
Yes, it is indeed in a .ogg file, which is not compatible with Itunes, so in the next step you'll learn how to convert it. If you want to use a file that is already in Itunes-compatible format, just skip ahead to step 4.
Also, interesting note, a great deal of classical music is in the public domain, and can be downloaded in this way off of Wikipedia.
Step 3: Convert the File
Remember how I mentioned VLC earlier? This is where it comes in handy. So boot it up.
Rather than spreading these instructions across like 7 steps, I'd rather just put them on one and explain with the screenshots. So...
1. Go to the upper left-hand corner and select Media->Convert/Save. Alternatively, just hit Ctrl+R
2.Select "Add..." in the File Tab
3. Select the audio file from your desktop, or wherever you downloaded it to
4. Click "Convert/Save" at the bottom of the menu after you have added the file
5. In the "Convert" window, click "Browse" for the destination file. Select your desktop as the destination, and rename the file whatever you want, as long as you remember to put a .mp3 extension on the filename.
6. Select "Audio-MP3" on the profile.
7. Hit "Start" It might not look like anything is happening, but wait a few seconds and check your desktop. The file should be sitting right there. Voila! Now to put it in Itunes!
Step 4: Put It in Itunes!
1. Right click on the file, select "Open With->Itunes". At this point Itunes should launch automatically, if it isn't running already
2. Find the file in Itunes if it isn't playing already
3.Right click on the track and select "Get Info"
4. Select the "Options" tab
5. Now select the portion of the track you want to use as the ringtone. Remember that it can't be more than 40 seconds. I chose the portion beginning at 2:22 and ended it at 3:00, using the "Start Time" and "Stop Time" checkboxes. Then hit ok
6. Right click on the track and select "Create AAC Version" This will create a copy of the song, but only the portion of it that you selected between the start and end times.
7. Now see in the list directly above the original file? There's the new copy. Just a few more steps!