help with network configuration

I have several computers in my home, configured on a
wireless network. I want to be sure I have the best
config for the home with respect to security. I suspect
that I do not, but want to check with you. Current config
is as follows:

Internet into DSL modem
DSL modem into WAN port on WAP (w/WEP enabled)
Machines plugged into ports on WAP with Ethernet cables:
1. Win2K Server
2. Win NT
Machines accessing WAP via Wifi:
1. Win2K laptop
2. WinXP Pro laptop

Some machines talk to others, some don't talk, some talk
to another but that one doesn't talk back, etc. Workable,
but hardly "right". My objective is to do it right, in
terms of communication and security.

Wondering what I'm missing, and appreciate any help.

Warm regards,
d