You can follow the following steps to do this on Facebook.
1. Read About The Process On Facebook
2. Create a "Fan Page"
3. Upload a Photo and Edit Your FanPage
4. Finally, Click the "Add Fan Box to Your Website" Link.
For "RichEdit" pages, you need to click on the <> icon to see the "source code" and paste the embed code right there.
Hit Save and You Should Have a Box Similar To the One Here:
Invisible Gold - Easy to Edit Websites on Facebook
Alternative: Facebook BadgeThere is another option if you just want to use your Facebook page itself rather than creating a FanPage. It's called a "Facebook Badge".
There is an option on the Profile page called "create a facebook badge". It works the same way. Just copy/paste the code they provide into your Invisible Gold powered site.
Create Your Badge