Iphone5 and ipod won't put any new music in artist section?

My iphone and my ipod all of a sudden have stoped putting artists in the artist section when i put the music on either device. I know all about "get info" and the artist name is all set, its not a "various artist" problem. I know the music has gone on to both devices though because the music can be accessed under albums and songs just not artist which is the easiest way to find things in my opinion.instead the artist section says i have no music?

When your iPhone storage is full what do you do?

Okay well my iPhone 4 is only 8 GB & its practically full, I have less than a GB left & when I connect it to my computer, 2.58 GB are tooken up by "other". What is it? I know what the rest are because they say apps, photos or music but most of my memory is tooken up by "other" but I don't know what that is.

What happens if i turn off Wi-Fi on my iphone 4?

I'm new to smartphones and i'm not really a tech whiz. I'm just wondering what happens if i turn off the Wi-Fi when i leave the house. Does it use3g and just connect to any network and use up my allowed megabytes or would it not do anything?

IPhone Sim Cards (Virgin Mobile)?

I currently have an iPhone 4 with Virgin Mobile's service. I'm interested in switching to straight talk's $45 plan simply because its a cheaper unlimited plan than virgin offers. However, Virgin phones don't use SIM cards and I know that you need one for straight talk. Because my phone doesn't use one, does that also mean it doesn't have the slot for one? If anyone knows from experience Please help me out.