all those companies have a fraud div, copy the e-mail and it's header and send it to them , they will tell you if it's real or not in six to twelve months if things are running smoothly.
FWIW, just forward those emails to spoof@paypal.com. I think they're interested in such things.
They are.. and they actually succeed. I forward the ones I get to spoof@paypal.com all the time.. and never get any repeat e-mails from the same sender. ( whereas other spam I get many ) There's also one for ebay ( spoof@ebay.com ) One of the isps on a spoof link was a sub-domain off of a yahoo account .. I forwarded it to yahoo's customer support pointing that out, and that site disappeared real quick.