There is a method suggested here:
http://www.outlook-tips.net/archives/2004/20041105.htm

Signature
Russ Valentine
[MVP-Outlook]
>I am trying to copy and paste a list of email addresses into a distribution
> list. Is this possible?
>
> thanks
>
> Nicole
David - 11 Oct 2005 11:00 GMT
You didn't specify from where you copy these addresses from. Assuming
that is from a file you can do that with Email Address Collector. I am
not sure if it can extract from the file you copied those addresses,
but you can try with it says it extracts for any local files. It can
import addresses from any type of file that contains email addresses
and exports them to CSV files or your Outlook Contacts groups.
You can find it here:
http://www.emailaddressmanager.com/features.html