for hosting your own websites
you need following:
1: very fast internet connection in terms of upstream
2: Static IP (optional)
3: Domain (again optional, as you can use your IP to get traffic in)
4: DNS Server (this is for free anyway)
Hardware:
1: you have the server already
2: Router (capable of opening ports) and best if it assist loop backs. (else get a dial up or use neighbours connection).
and that's about it.
for Linux, you;ll be using Apache, which I cannot help you much as its Command Interface Webserver, but I can only assist in Windows Based IIS.
and BTW, with Netfinity 4500R, you cannot expect high performance. its a P-3 based unit.