Ok so the recent iPhone OS 3.0 update has a lot of features but the biggest hype about it can be concluded in four points...
The first three work fine but MMS doesn't work every time. Turns out the MMS APN setting gets reset after a while.
Now I'm not sure whether it's a bug in OS 3.0 or if there's anything causing the problem but what I know for sure is that it just won't remain there; it simply disappears without any reasonable cause.
I tried everything to store the APN (mms.wataniya.com) but it just won't happen. Everytime I do I go back to network settings to find out it's not there anymore.
The only method I found out to keep it working is to restart the iPhone, go to Settings > General > Networking > Cellular Data Network and re-enter the APN again and NEVER connect the iPhone to anything, neither a computer nor WiFi network!
Anyone having the same problem?
UPDATE: Problem resolved...
To avoid this problem you need to enter the APN for both Cellular Data and MMS.