I've read several posts about PIN messages and their popularity, I'm not sure what differentiates them from SMS unless its similar to NETSEND on a LAN, however I was thinking that it might make sense to have a line in the address field for a PIN # rather than having to memorize it.... any thoughts?

There is a line in the address book for PIN...

That's a very good point. Guess that problem's solved. Back to my first question, what's the point of PIN over SMS?

PIN is only available to BB users

Aren't PIN messages also part of the unlimited data package where SMS messages require a separate text message plan or are charged for individually?

correct

Also, PIN messages give you an easy delivery confirmation. I've also read some comments here about security and maximum message length, but I don't have any first-hand info on those subjects.