Unlocking a phone will void the warenty, so while its not illigal, it will violate the carrier's TOS, and you could be fined by them, depending on their terms of service
Since this phone is for Telus, Which uses a CDMA Network, it should work on hte Virgin Mobile network, as long as you plan on using it within USA or Canada, which vigrin mobile also uses CDMA in these area's, how ever, it will not work on vigin mobile networks over seas, or on the canadian: Rogers Wireless, or Fido Networks as they all use GSM networks.
Source:
http://en.wikipedia.org/wiki/TELUS
http://en.wikipedia.org/wiki/Virgin_Mobile
And the last 3 weeks of Wireless tech support training for Rogers Wireless
/ 
