I misfired a little with DynDNS, this is more commonly used to permit web access to your own server from a remote site. You register your name with them, install the free client on your machine then connect at will. I have it coupled with a free http server for file transfer and it works well. If you had a small number of customers to service, you could set each of them up as hosts, but it wouldn't suit a larger operation. Teamviewer is the go for you I think.
Chris B
http://www.dyndns.com/services/dns/dyndns/