Using the 220-age gives me 193 for a max. I hit 206 in my cross race over the weekend, and commonly push 190-200 running intervals on the track. Absolute max currently is 218, based on the "push yourself until you're sick, then push a bit harder" method. Basicaly, warm up fully (20-30 min running, plus some fast 100m strides) then run an all out 400m, making sure you're spent at the line, and continue to run another 100 at the same pace (or as near as your legs will allow). Let your HRM keep recording for the next minute to ensure your HR peaks as it will tend to lag 10-20 seconds. Similarly, for your bike max, warm up fully and hit a 90 sec all out effort, then continue it for 30 more. Make sure your mind tells you that you're spent after the first 90 (you're not, the mind just says you are to protect the body). Swimming max can be determined similarly. 200 sprint, making sure you're gassed at 150, then sprinting another lap. You'll look pretty funny gasping for air with your arms flailing about at the end, so you may want to do this during low time at the pool...

As for max HR being sport dependent... no. If you're well trained, they may vary a couple bpm between them, but should be negligible. Your heart is capable of working at a certain rate. Your specific muscles may not be efficient enough to utiize the O2 the heart is supplying though. Training causes them to adapt, and is why we do it. Over time, and with increased levels of training, you will find your max HR's to converge to one absolute number.

I agree with TriSooner, provided that you are comfortable that you really are hitting over 201/202. It's certainly possible, but I have some intermittent issues with my Garmin 305 where it shows spikes over 200 when I know I'm not pushing very hard (RPE 7-8). As least mine seems to be sensitive to nearby electrical interference.