Like the subject says when I do speed test I am somewhere around 2mbs download, but when I actually download a file it is only around 150kbs. I have tried this with several files.

I was wondering the same thing. My speedtest shows the 3G at 2.5mbps and my wifi at only 1.5mbps (I only have DSL available). The 3G seems pretty fast, but not as quick as the wifi. I think the speedtest is wrong.

It helps if you can see the latency in your speed test, too. There probably is more latency on 3G than on your DSL/wifi, though that can vary. Also the 3G speed can vary widely minute to minute. I've experienced that more than once. And yes, speed tests can be wrong. Which speed test app or speed test site are you using?

I generally use at least two different speed tests when accuracy matters, and from each server run a few for consistency. You're probably aware of this but since it hasn't been mentioned, when downloading files your speeds will only be as good as the rate that the source can upload too. I'm not an expert on the speed test apps for the iPad, others will be better suited to point you in the right direction there.