Did you know you can create custom landing pages for your business on Facebook?
If you have a "fan" page for your business, you can use FBML or straight HTML to add a customized tab on your fan page, essentially allowing you to build a website within your fan page. You can also set this tab to be the first thing new people to your page will see, so if they don't "like" you yet, they'll go there instead of to your wall.
Important note: This doesn't work for groups or individual pages - only for fan pages.
What does this mean to you?
If you have a business, you don't want to set up a group. You want to set up a fan page.