I filed my taxes online last year and need to get a copy of my 2006 returns to file an emended tax return. I wanted to know if I could simply find them online or do I actually have to deal with the IRS

You should always make a copy of your tax return for your records!

No way to get a copy from the IRS online. You can request either a complete copy from the IRS - it takes 2 months or so and will cost you $39. Or you can request a transcript, which contains the same information but is in a shortened version - that will take about 2 weeks and is free. See the following for details on how to request this: Frequently Asked Questions - Keyword: Past/Previous Years' Tax Returns