Apple iPhone 3GS

I just updated to 3.1.2? i think it was, the latest version of the Iphone OS (update as of 10/10/09) and since then i have had to reset my Iphone to factory settings TWICE!!! My Iphone puts all my music on the ipod and switches it from "Music" to "other" thus not allowing me to play them. When i connect it to itunes on my computer it shows that i have all the memory from my music but its not viewable, you cant view files in the "other" category.

Im really frusturated because it takes like 1 hr 30mins to get my memory back on the iphone.

Any ideas?