Text shows up as an email address instead of phone number.

I bought a Verizon iPhone 4 as a Christmas gift for myself and got one for my wife as well.

I transferred my contacts from my droid to the iPhone with no problems. I can text my wife and it works as it should. Although, when I text a co-worker that has had his iPhone for almost a year, Instead of it showing my number/ contact name from his address book, it shows my apple ID email address.

What do I or he need to do to correct this problem?