which is why I have my reseller account with them - on which many of my clients' sites are hosted.
The answer to your question is yes, you can indeed transfer your name into your Plus.net account. Contact the company which is currently hosting the name, and ask them to retag the name to:-
and to change the DNS details to:-
Primary Name server 1 - ns1.force9.net - 22.214.171.124
Secondary Name server 2 - ns2.force9.net - 126.96.36.199
Then access your account with Plus.net and follow the instructions to transfer a name in.