I've noticed that our bathroom sink water pressure is considerably lower than in the past. It used flow full-blast, and not it just trickles slowly.

All other sinks in our house seem to work fine. I've tried adjusting the valves under the sink, and that has had not helped. We have very hard water in our house, so I suspect that there is some calcium build-up. Wondering if anyone can suggest what to do? If I need to take the faucet apart and clean it, I'm willing, but have never done this before so not sure where to start.

Here's a YouTube video of the problem:
http://www.youtube.com/watch?v=NPPn72sF5DI

Before doing anything drastic remove the aerator screen from the faucet spout. How to Clean or Replace a Faucet Aerator - Plumbing Repair Guide - ACME HOW TO.com Do you now get that full volume like you used to get?