The Profile HTML Facebook Application is a gift from the coding heavens. If you need to get HTML code onto your Facebook Profile or Page (yes, Page as well!), the Profile HTML app can handle it in the way you'd expect!
Do a search for "Profile HTML" at Facebook, or click here for Profile HTML. The directions for how to make it work are really simple, in fact, I'm wracking my brain for what to tell you. Literally, Profile HTML is the equivalent of a point and shoot. Of course, you'd need code that already works...but I'm sure you have that.
Once the HTML box is enabled for your Profile or Page, get the code you would like to add. Copy the code and paste into the large text box that the Profile HTML application provides once you sign up for it. Click "Submit" below the box. Voila. Now go view your Profile or Page.
The application was designed to work in the narrow side column or in the wider main body. If your code is of primary importance, drag it to the top of your page. You can click on the heading part (usually the blue bar across the top of the box for the Profile HTML application) and drag it to where you'd like on your Profile or Page.
You can have more than one HTML box on your Profile or Page. If you have more than one Page at Facebook, you can sign up for each page and add a box of code.
TIP: To get an element off of your website, like a form, right click on your page and select "View Source" or the like. Find the code and highlight it to copy/paste it later into your Profile HTML app.
TIP: If you grab code off of your website to be placed into Profile HTML, and if that code contains images, make sure your web address is included in the code you are using at Profile HTML. Most times, the code for an image or an interior link will omit the http://www.yourwebsite.com. It will start with something like /images/yourimage.jpg. Just make sure that http://www.yourwebsite.com/ is included before images and previously interior links. I say "previously" because now that this code is in Facebook, you are creating an exterior link to your website ("exterior" meaning from another website).
I have also dabbled with the Extended Info application. It did not work as I expected, so did not put much time into it. It may be useful for some purposes, but right now, the Profile HTML application did exactly what I needed.