Motherboard: Abit NF7-S v2
this board is one of the best socket A's for overclocking your XP processors (very simple, and at times can be fun.)
CPU: Athlon XP-Mobile 2600+
This is the AMD equivalent of a pentium 2.6 gig processor. But since iit is a mobile processor, it takes less voltage, wich therefore keeps temps lower. This allows for easy overclocking, and you will be able to bring it up to atleast 2.2 gigs no problem, which is the equavalent of a pentium 3.2 gig processor. Great Value
CPU FAN: Thermaltake Volcano 12+
You have to have one of these or you will fry your system. This thing is a beast and is probably the best socket a cooler out there. It is EXTREMELY loud when turned on full blast, but luckely there is a fan controller to fit your needs. Can be silent if needed.
RAM: Corsair 512MB Value
Same as you had before. Great choice. Corsairs a good company and makes cheap, quality ram.
Hard Drive: Maxtor 200GB S-ATA HD
its about 10 bucks more than what you had, but you will appreciate SATA beacuse its speed. Only thing is that it takes a bit to setup, but once its ready its great.
Video Card: Sapphire 9600XT
A lot of people have it, it is cheap, and most love it. It will probably play any game at all right now. Its got a great price/performance ratio.
Those are the most important parts. All you need now is a case, power supply, monitor, and CD-ROM/CD-RW/DVD drives.
I highly suggest picking up 2-3 case fans to keep good airflow going. Check to see how many your case comes with and see if a few more would work. Also, pick up a floppy drive. You need it to install SATA, and its just good to have.
BTW, heres a link to a nice cheap case fan:
have fun and ask more questions if you need help.