Prepaid SIM in Italy?

[dr0ss]

I'll be in Italy next month with my family; I would like to get SIMs both for my phone and for my son's. I see that Wind has a promo on called the "Noi Wind Pack" which offers:

Fino all’8 giugno 2008 è disponibile, a soli 15 euro, l’esclusivo Noi Wind Pack, 3 SIM Wind con 5 euro di traffico incluso che parlano e inviano SMS GRATIS tra loro!

If I am reading it right, this lets me buy 3 SIMs for 15 euros, with 5 euros talk time (on just one, or 5 euros apiece?) and exceptional rates between the 3 SIMS. My questions are (a) Am I interpreting this offer correctly? I do not trust my Italian on this, the deal seems too good to be true. (b) It seems to auto-renew after the first month; if I only need it for a month, would the right strategy be to simply cancel the plan after a couple of weeks? (c) My son (and his phone) will actually not be joining me until a week after I'm there; is this a problem w/r to activation (eg, can I activate all the SIMS just in the one phone)? A thousand thanks in advance for any advice. - DR