You do understand that pptp has been deprecated and is no longer considered secure. And that ssl is where everyone is going because of ease of doing it, no special protocols have to be open, etc. Its 1 port not many with multiple protocols involved.
But if your wishing to have some dedicated server or vps sitting in a colo/datacenter somewhere - then sure fire it up. 2k8 and 2012 both have vpn support built right in. Its rare that a dedicated server or vps would have any ports/protocols blocked so you should be free to run whatever vpn you want.
I have a linux vps that I run for testing reasons and as a means of a vpn if my home connection is down and I am out and about, etc. Its only 15 a year sort of box. Not a lot of umph to it - but it runs openvpn just fine only firewall between it and the internet is the one running on the host that I manage, etc. I would assume this should be the same for any server your renting or coloing, etc.
But it could be against your TOS?? to run a vpn? And comes down to what your doing using the vpn - you could prob get into some issues if doing p2p using it, etc.
as to pptp on 2k8 here you go
Configure PPTP-based Remote Access