Remote Access from PC to Mac

Hello,
I have a few Mac OS X units in remote locations (via PNT circuit, within my private address space) and I'm looking at any possible solutions for being able to gain access to my Mac machines from a windows PC.  Currently for PC-to-PC connections I am using dameware.  Love the programs simplicity, especially the fact that I do not need to have the host software installed prior to attempting to connect.  I doubt there is anything out there that can do that exactly.

I've been looking at VNC, but it's a bit more complex to have my very much non-techie user set it up via phone.  

I'm currently using webex, which is slow and a pain in the behind.

I'm open to suggestions, freeware or payware, I don't really care.