My iPhone 3G is currently showing 3.1GB of 'Other' disk space in iTunes, and this amount seems to be growing by about 0.1GB every couple of days. I can't find any good references for what this space could actually be getting used for.
I've heard of doing a restore to clear it up, which works, for about a day, but then the 'Other' space starts to quickly accumulate again.
I've also done all the Internet history clearing, turning off of indexing and removing of disabled mail accounts, still no success. I'd love to know how to either clear this stuff up, or see a decent explanation for why my phone is using all this extra space.
Here's a snapshot of what my disk usage bar in iTunes looks like:
UPDATE: My phone is not jailbroken. It is stock IOS 4.2.1.