Can you get a top up to to an iPhone which has internet?
You can get it from: 02, Vodafone, Orange, Tesco Mobile
Can i use a separate phone contract with free internet sim in a new iPhone 3GS and still use the iPhone on its internet for free?
depending on what plan you go on could be between 30 and 70 pounds
How much do you pay for internet and GPS and other stuff that connect to internet on the IPhone 4 with Fido?
Yes and you can change it in the settings option.
Should I buy an iphone 4 now or wait for the iphone 5 PS I have the 1st gen iPhone so i wanna new phone but w8ing seems better because they keep releassing new models every year which is annoying?
Depends, if you really want the iPhone 5 then you should get it if you don't mind spending more money on it. I'd wait.
If the iphone 3gs internet faster if the wifi is on even if you pay for the internet?
It's either compatibile with International Mobile Telecommunications 2000 (IMT-2000 or 3G) and/or the phone is the third generation of it's model.