unlockit.co.nz now has the new option of enabling MMS and tethering + MMS on your iPhone 3G with a configuration file. At the moment it does not set the MMS servers for people’s carriers so you will have to add these by hand. If you have the settings for various providers please contact me.
A few other websites have “popped up” who have tried to copy my website/idea but this is the original one trusted by 100000+ users in the last few months. We sign our profiles these days so you can trust that the config files won’t set anything nasty with them (which you can actually do) so be warned using other random mobileconfig files from around the internet.