Leading '1' in contact's phone numbers

[shawn sullivan]

Hey all,

I've noticed that when I get a SMS message back, or a phone number shows 
up, it's displayed as 1-XXX-XXX-XXXX, and it's unrecognized by my 
address book.

i'm working to import my contacts from Thunderbird, should I add the 
nation code to the front of the numbers so that caller ID will work, or 
is there something else I can do?

Thx. . .shawn