Two words - JUST DO IT!!! ok... that's three words, but the point remains!
I've been pondering doing this for a while, finally bit the bullet and purchased a Corsair 'Force Series' 60GB SSD for £100 from scan.co.uk. Just completed installing it and all I can say is, WOW, what a difference it makes... granted it's a fresh install of Windows 7, but boot times have been slashed to around 10-15sec (I'd say at least 50% faster, if not more).
What's even better is that as soon as the desktop is open you can do things, no waiting around for a bit while your startup programs load... it's awesome! I'll get used to it pretty quickly (as you always do with any performance boost) but for the moment it really is superb! Also, everything just 'feels' snappier, programs are opening in a blink as do windows etc, it all 'feels' much much quicker to use...
BTW, I'm no IT techie, just a home PC builder/enthusiast, so don't bombard me with technical questions, I probably won't be able to answer them