Making free ringtones on Linux is very easy. All you need is an audio file (like an MP3 of your favorite song), and a free sound editing program called Audacity.
Check out this EDU spam result at #4 in Google for ringtones:

As usual, it's an EDU site. Clicking on that #4 result takes you to this page on a community college's Web site:

Clicking on any of the the links takes the visitor to an intermediate page — the URL shown in the middle of the page.
That page has the following code — I've highlighted the interesting parts:
Google has finally lost the ongoing ringtones spam battle. Spammers have achieved #1, #2, and #4 for ringtones as shown in the image below.

In a recent post I pointed out an amazing case of a spammer putting Google Docs spam at #2 for ringtones. I've been checking lately and much of the top 100 results for ringtones are just blogspot spam and spam on .edu domains.
Today Google was getting hammered by ringtone spam. I wish I had taken a screenshot a few hours ago because it was worse. In the screenshot below, results numbers 2, 3, 4, 6 and 9 for the highly competitive keyword ringtones are spam.
I was shown an interesting search result a couple of days ago.
Here are the Google results for the keyword ringtones from January 16, 2007 — notice that the #2 result is Google Docs:

Clicking on the link takes one to the Google Docs page shown below: