This is probably going to be a really short page, because it actually quite easy to make a QR code. You don't need to know anything about writing code or really know anything about QR codes to do it. This is the easiest site I have found so far for making the codes: http://qrcode.kaywa.com/
You can select content type as either URL, text, phone number, or SMS (text message).
So that's where the QR code originally came from, but let's go back to the history of the original barcode:
If you select URL as content type, simply enter any URL (I would suggest doing your Facebook page, LinkedIn page, blog, or personal website) then click generate. You can change the size of the QR code for aesthetic purposes, but it doesn't make a difference as to how the QR code works. When you scan the generated code with your phone it will open the selected URL on your phone.
For the text option, write anything you wish. When you scan the code with your phone, it will open the message in the notes section.
The phone number option allows you to enter a phone number that will create a code that when scanned will open the phone number in your phone so that you can add it to your contacts or call the number.
The SMS option allows you to write a text message that you can send once you scan the code with your QR code reader. You enter the person's phone number in the Nr: section and the message underneath that.
Using whatever option you choose, once you create the code, the site gives provides the image in an html code so you can add it to your website if you wish.
Here's another generator that's a little more complex: http://www.qrstuff.com/
It has more options for where the code can take you such as Google map coordinates, a twitter status update, or a PayPal buy now link. You can also change the color of the QR code; it has to be a solid color though. It also has options to print and download the code, or you can also get it printed on t-shirts, pins, hats, and a bunch of other stuff.
Hope you enjoy making your customized QR codes.