This isn't so much a "tour" as it is an overview of the site - what you can do with it, and what it can do for you.
Obviously, you'll need to register first. Enter your email address, first and last name, and year of graduation into the form, and hit the button. A confirmation email will arrive shortly (under 5 minutes, generally). You'll need to click on the link and set up a password, and your housing information. And that's it!
So you're registered. Now what?
Once you log in through the field on the top-right, you're greeted with your home page - a one-stop page where you can view recent comments, add DVDs, and do a quick search by title.
The My DVDs page is the second tab in the navigation bar. When you click on it, you're taken to your DVD collection. A listing of all of your DVDs is there, and you can sort it either by alphabetical order, or by your rating. You can rate DVDs directly from that page, or click on the titles to go that DVD's page. You can also remove a DVD from your collection if you added it by mistake, or no longer own it or are comfortable sharing it.
A DVD Page is where you can find out more about a movie before requesting it. You can see the overall rating from all colleges, the average rating from your college, and reviews from Amazon and from other Movie Moocher members. You can rate it or write a short review if you've seen it, tag it with keywords, or buy it from Amazon if you just have to own it. You can also request a DVD from other members from its page.
You'll want to look at a member's Profile Page before lending them your precious DVD. On this page you can see what others had to say about them - if they beat up someone's DVD in the past, you can read the sordid details here. On the other hand, if they got glowing reviews from others, it's likely you can safely lend it to them. On a similar note, be sure to leave feedback about other members' borrowing habits. If they were good or bad to your DVDs, let it be known. You can also see some of the movies that that user has to offer.
Searching is one area where Movie Moocher really shines. You can specify a huge amount of search parameters, and find exactly what you're looking for. Don't know the title? Look it up by keyword! If someone's tagged it, it will show up. Are you looking for a science fiction movie that's between 90 and 120 minutes? You can find it. Are you looking for the top-rated TV shows? Do a search for "Season", and sort it by rating. You can click on any of the search results to be taken to that DVD's page, where further options await.