hi mate,
Ive got an A3 myself. Good bit of kit, i got mine of ebay too.
use that website that already been linked to, its a great site.
You dont actually need to buy the SPC-01 card or any other card infact. From that site you can download the Sysex files and upload them via midi from your PC to your A3. You might need to get a USB to midi cable (£50 in UK, $50 in the USA)
Your right in the fact they Edge uses (or at least used to use) the A3 for The Fly, Mysterious and Numb.
As with any multi effect processor, you can achieve almost any song out of it with some fiddling. Especially with the SPC cards uploaded.
Ive just bought the SPC-01 card from Ebay, keep an eye out on there if you want the actual cards, but be prepared to wait and pay over the odds for them as they are gold dust.
Just shout if you need any help. !
ben@foster.net and ill see what i can do.
You might want to check out setting 27 - its called The Edge. Its a good starting ground for most U2 songs, just alter the delay to suit the song. - i dont know your level of playing, but i found it a good starting block when I got my A3.