Can I use my IPhone (Verizon) in India?

I'm going for vacation for a month and I wanted to know if I could use my iPhone there. I probably won't be using data but a simple call here or there. Do I need to buy a plan to do this?

What is taking up so much space on iCloud?

I'm starting to get very frustrated with my iPhone 4s.ever since i updated to ios 6, icloud won't update anymore. It says there's not enough storage. This is weird because i only have it set to back up my contacts and pictures, no apps or anything else. I only have 600 pictures and about 400 contacts.icloud says the next backup would be 6.6gb. I don't see how about 2gb of pictures and 1gb of contacts adds up to that. I have tried deleting the backup. So now, there's no backup for my phone. I have deleted everything.safari data, messages, calls, everything.nothing works. So please help me.

Why any of my iPhone apps are not supporting my phone?

I got iPhone 3G and I need a few apps on my phone, for some reason any iPhone apps are not working. They are asking for updated software version. Is apple forcing me to buy a new iPhone? Or am I missing something here?

Added (1). My iPhone software is up to date iOS 4.2.1according to iTunes

Why does my iPhone lose so much batter when it's off?

So I have an iPhone 4S that I often use to play games. It does not have that many apps, only the base apps and around 15 extra. When I turn it off for 20 minutes uncharged, it loses 8% battery from 100%. I've turned off Bluetooth and Data Roaming, and I turned off all Notifications. My brightness is only at 25%.Is there an explanation for this mysterious draining of my battery? My iPhone is around 1.5 years old.

Added (1). I mean battery, btw. Oh yeah, and it's Jailbroken, but I haven't used it to download anything that would make my phone run down…

Why does the music on my iPhone 4S crash?

Okay so I open my camera (no, it is NOT on video setting, I know the music fades when the video is on) and it just crashes. I have an iPhone 4S, and lately it's been laggy and crashing. Can anyone please help me? It's driving me crazy! Also, it just sometimes crashes all of the sudden. I have turned off the Facebook from your phone thing, because I read that it makes your phone messed up. I delete apps running in the background every time I'm done on my phone for a while. Please please help.
~Holly Rae