Re: "Do you need 2 graphic card ports to do duel graphic cards?"
Yes, for Sli (multi-nVidia GeForce cards) and Crossfire (Multi-ATI/AMD Radeon cards), you need 2 or more graphics ports i.e. 2x PCI-E 2.0 ports (AGP is dead now). A PCI-E x16 port and a PCI-E x8 port is the minimum you should have for dual cards (they will run in x8, x8).
The cards need to be the same e.g 2x nVidia GeForce 9800GT's or 2x ATI Radeon HD 4870's - although there is something called "hybrid Sli (or) Crossfire" - can't remeber which. This is when you have an nVidia board I think (or an ATI one) and you run a graphics card in hybrid SLi/Crossfire with the integrated graphics on the board if there is any.