Increase leg speed (max cadence)

Agree - don't try high speed cadence drills out the saddle - one slip and it'll be painful because there's still a lot of energy being generated at these leg speeds. Whilst high-speed drills aren't really representative of racing conditions, I find they're really good maximum threshold efforts - I can manage more of these than I can 'grinding them out' - the whole trick is to keep it smooth rather than stomping the pedals.

Thought I was watching my washing machine on spin cycle mode!

Brilliant!

(Will start to cruise at 100 rpm now)

Doing RPMs over 180 requires a small gear. Its technique more than strength, although its the fast-twitch sprinters that have the best rollapaluza times. But a smooth controlled whippet can beat a big guy who smashes around. Its all anaerobic, so nothing endurance. thats essentially impossible at those speeds. You don't even need to breath....The oxygen debt afterwards is mental though.
But no-one should be having an average cadence below 80rpm, even 90. Its not good for you and not efficient. Most pros will spin closer to 100. Canc spins at 110 in TTs. That is not really spin training per se, though I guess it is if you're doing 70rpm!
Its all about pulling and pushing across the whole stroke. An easy way is to image you want to pedal in 'squares', push forward to 3pm, down to 6pm, back to 9pm, up to Noon on your cranks. That will get you there.
Also, force yourself to go 2 gears below what you would normally. Of course, you need a great position on the bike, and nice flat tracking of knees (no bobbling out).
Regards sprinting at high revs, don't try sprinting out the saddle at 225rpm, you'll kill yourself! You need to be seated.

Check out these links:
Its all about technique, concentration and stability. No mashing!
http://www.youtube.com/watch?v=sVbwngNoHm0

http://www.youtube.com/watch?v=Jgyq8Zkp10Y

Go for it!

Just remember to strengthen your joints and
allow good recovery before you go flat out.

I think most of us could do it before going
pop! Last thing you need is an injury.

Do plenty of research & understand it.

90 rpm cruising then 110 for short blasts.

180+ is pretty dam good for sprints. But that's 3 revolutions per second. Are you going for
Endurance or sprints?

Fixed gears, shorter cranks and a turbo trainer or rollers will see me good for 240rpm plus - it starts getting a bit blurry after that! It's quite tricky to set up many spin bikes like a road bike too - Q-factor if often way too big and the big squishy saddle just causes you to bounce more IME.

180-225? Hmmmm fine for a short stint but a thats not spinning in my opinion, thats just an interval you add to your spinning

For instance, i've just come back from the local gym, first time i've been there is 7 years, i just fancied a swim and a couple of mates were going

Jumped on one of their bikes, did interval's for an hour, highest rpm i got was 147 and my average over the hour was 88, quite happy with that, but was glad to hit the pool

225? Jeez...I'm impressed, I can't imagine that fast

get a fixed gear with a low 'gear', say 63, or lower and ride down some big hills..

I love doing Rollapaluza and spinning at silly speeds.

Spinning actually can be a great way to increase speed. The bikes should be flywheel, so you can be smooth, not clunky. Just don't stop suddenly! I practice by doing all-out spin sprints for 20-30 seconds, reaching 225+.

Otherwise, rollers can be useful, or just setting a low gear on the road bike, though far harder, as its likely you'll not have a rounded stroke, so you'll start clunking at weak points.

Technique is a big part though. Keep the body still, locked with your core, and just concentrate on keeping the stroke smooth, don't smash at it.

180 rpm? I'd like to see that. Pros only spin in the low hundreds (ish). I average 70-75 on a good day (and 15-20 uphill!).