These are links that I used. I believe they will be important to you too.

1. College Board
This is the site where you register for the SAT's and also search for schools. See: Study in the USA, Step 1

If you're writing the TOEFL Test, this is where you should be heading.

3. OANDA currency converter
For currency exchange rates, currency converter, etc. I like this site a lot, very easy to use.

4. Google
Very popular, yet underrated. A lot of people ask questions, and wait for answers for ages - questions that they easily could have googled and come up with answers almost immediately. I know there are other search engines out there, but google is what I've always used, and still use.