While the Tab doesn't have a wi-fi only option you can don't have to get a data contract.
1) Get an AT&T Tab - No contract required, No data plan activation required. I'm sure about this one; I own it.
2) Try the carrier activation bypass hack.
In what could be the easiest hack ever, Thoughts From the Sidelines is detailing a way to bypass carrier activation. This would effectively giving you a WiFi only Galaxy Tab. They report the steps may take several tries before it works.
- Press “Volume Up” one time
- Press “Volume Down” two times
- Press “Volume Up” three times
- Press “Volume Down” four times
Don't let the data plan commitment keep you from getting the Tab!