Hi, I am getting an iPhone 4s, currently I have an iPod Touch, can I use the same apple ID for the apps and as the iPhone memory isn't as big as the iPod how do i go about only putting certain things (music, video, apps) on the iPhone?

yes you use the same AppleID.
you manage all your content via itunes (same as you do with the ipod touch), so pick and choose what you want from there.