SwirlySpace has managed to enable MMS on iPad 3G with their modified SwirlyMMS app for jailbroken iPhone. The video posted below demonstrates that iPad 3G can natively send and receive MMS & SMS.
Please note that SwirlyMMS is sending MMS *natively* via carrier networks and NOT via SwirlyMMS own service SwirlyNet.
The SwirlyMMS app is not quite ready yet for the iPad. The developer is working on its GUI for the iPad, rest of the stuff is already done and allows SwirlyMMS to send and receive MMS and SMS using the iPad!
Last week, Musclenerd had demonstrated sending SMS from iPad.
Update 1: Download iOS 3.2.1
Update 2: Save SHSH blobs for iPad