I am looking into getting an iPad ... I'm
Not sure which one to get I was thinking just the 16gb wifi version... But I'd it worth the extra for the 3G wifi version?? If do can i use the micro sim in my iPhone 4 for data?? Is this possible??

One option is to Jailbreak your iPhone and install MyWi 4.0. The problem is newer iPhone contracts don't give much data allowance these days, so you'll soon run out if you're intending to use 3G data a lot.

iPad 2 is supposedly due out in January or February next year, is it really worth purchasing one right now?

If jailbreaking your iPhone doesn't do it for you, you might consider 3's MiFi. The pay-as-you-go version has a higher up- front cost but you only need to top it up when you need it. Downside is it's another device to remember to carry/charge etc.