http://phobos.apple.com/WebObjects/MZStore.woa/wa/
viewCustomPage?name=pageSNL&ign-mscache=1
(Broken into two lines for a narrower display here.) Well and good. Type that into your web browser, and you've got iTunes opening the SNL page. So, I tried to circumvent this automagic opening of iTunes; I popped open the OS X Terminal application and typed the following:
curl "http://phobos.apple.com/WebObjects/MZStore.woa/\
wa/viewCustomPage?name=pageSNL&ign-mscache=1"
curl is just a way of downloading the source code of a specified page, for those of you who don't know. It worked, and returned the source code for the page. I skimmed the JavaScript functions in the source, and went to the bottom section of the code. When the body loads, a URL is opened in iTunes. I copied and pasted the first link I found there into Safari. As expected, it opened in iTunes, obviously, as the protocol is itms://; why not just change it to http://?
I did, and the resulting link will will load in your web browser. It just loads the main content of the page, no formatting, but all the source code is there. Browsing it, you'll see all of the XML tags which iTunes takes and makes a beautiful page with. It's not very useful, but it's fun nonetheless!
In summation, to turn a standard iTMS link into a web-browser-ready page, just change the phobos.apple.com server to ax.phobos.apple.com.edgesuite.net, and change the itms:// into http://.
[robg adds: Opening the page in Firefox is much more interesting than in Safari; Safari attempts to interpret the XML, whereas Firefox will just display it in its raw XML format. And yes, this is mainly a hint for the ultra-curious who just like to dig into everything :).]

