I plugged my phone into the laptop this morning (primarily to charge it) and itunes informed me that there was a software and a firmware update for my phone, and would i like to update.
All went well, can't see a lot of difference other than the homescreen now stays beind the icons all of the time.

The annoying thing is that my MMS settings have all disappeared and I am unable to use MMS.

Being with T-Mobile, I had to input the settings myself but surely I need only do this once?

Is it normal to have to re-input settings after an update? No other settings have been changed (nothing i've noticed anyway)

I'll not bother with any updating in future if I then have set up the phone again!

Which version did you upgrade from and to?

No change here. My iTunes says 4.0 is still the latest version.

If you upgrade the firmware on an iPhone, does it not delete all the settings on it first?

When I did my O2 iPhone, after updating it told me there were some updated O2 settings to download which it did and installed to the iPhone for me.

As the iPhone is currently unavailable for T-Mobile, there wont be any setting from iTunes to download and install automatically, so I'm guessing that yes, you'll have to do it again yourself until the time comes when the iPhone is available on T-Mobile and they make the settings an automatic feature.

Upgraded to version 4 from whatever the previous one was.