Is there tax on the Online Apple Store?

Yes. I got charged tax when I bought my MBP last month. I also get charged tax on iTunes purchases.

How much was it for the MBP because that is the one I am getting and where is it since tax is measured in where you live.

In my case it was 8.25%, I live in Texas.

The government charge VAT, as they do with any purchase. If you can claim VAT back, then you do so after sales.

Yes. I believe the Apple Online Store has tax charged on it, so do apps from the App Store on iTunes.

They charge tax based on where the item is shipping. I believe online stores only have to charge tax in states where they have a retail presence. So in theory if you lived in a state with no brick and mortar Apple Store, you might not be charged tax.

I’m only speculating as I live in California so I don’t have any first-hand experience with ordering from another state.

Not for software, when I downloaded Lion it was 29.99 as advertised.