New Desktop for VOIP use

I am planning to buy a new PC for the purpose of making pc to pc calls (VOIP) ( webcam) and some word processing.

What pc requirement is needed. Please advice. What OS should I use?

below are tips I gathered from the internet:

CPU >400MHz
RAM 512MB upgradeable to 1 GB

A full duplex sound device (both parties can talk and hear each other at the same time), speaker/headset, and a microphone (Road Warrior only).

USB 2.0 (Hi-Speed USB) (Type A and Type B)

Processor Pentium 133 MHz or higher processor required for all operating systems.

Disk drives CD-ROM drive.
Monitor VGA or higher-resolution monitor; Super VGA recommended.

Hardware accelerating cards
Special cards with hardware accelerating capability can be used. They are:
• Quicknet PhoneJack
• Quicknet LineJack
• VoiceTronix V4PCI
• VoiceTronix VPB4
• VoiceTronix VPB8L
Quicknet PhoneJack is a sound card that can use standard algorithms to compress audio stream like G723.1 (section 4.3) down to 4.1 Kbps rate. It can be connected directly to a phone (POTS port) or a couple mic-speaker. It has an ISA or a PCI connector bus.

Quicknet LineJack works like PhoneJack with some addition features (see next).

VoiceTronix V4PCI is a PCI card pretty like Quicknet LineJack but with 4 phone ports

VoiceTronix VPB4 is a ISA card equivalent to V4PCI.

VoiceTronix VPB8L is a logging card with 8 ports.

Any current (new) computer will do fine. You just have to choose a good web cam for quality video. VOIP quality might depend slightly on provider and harware used. Windows XP will work fine.

Here is some VOIP info: