Anyone have any success with VNC and remote logins?

I need some resources for the following:

My next project is to VNC into my home computer from work. Additionally, I want to be able to VNC into an XP computer (from my linux macine), which is owned by a friend of mine, who I’ve been helping with ram upgrades and virus protection. This would help me by making his system accessible from my home!

Is static IP essential? what do I do with the number I get form IP sites like www.ipchicken.com ? How is it different form my IP address on my computers? Is VNC even the best option? Has anyone else had success with this?

I can remote login to my internal network, but this seems to be a bit more difficult.

Thanks a lot for reading