How do I improve latency when playing games online?

[purecomedy]

I've been away from the online gaming scene for a while now. I was playing some Command and Conquer vs. a friend and we noticed some pretty harsh lag through most of the game. Here are as many details that I could think of that would matter:

-We live relatively close, about 50 km (~30 miles) away, both use the same cable internet service. I know when I did a test I could get about 5mbps

-I use a BEFSR41 10/100 Linksys router, my friend uses the Wireless G Linksys Router (NO Speedbooster) and I think he gets somewhere around 25-30 mbps connection. His router is upstairs in a 2-storey "normal wooden" house, his gaming computer is in the basement lets say 40 feet apart or so.

-I have applied the Windows XP speed patches from Speedguide, he has standard Windows XP settings for TCP/IP etc.

-I have turned Windows firewall off, I believe he has as well but not 100% sure. Both of us have SP2 installed.

-We are both using ZoneAlarm Pro in addition to our routers.

-We both have fast enough machines, P4 2.8C here and he's got a 2600+

What things should we try first? I know I could get him to apply the speedguide patches, but I'm not sure if those patches are to get a maximum download speed or to minimize latency (or do they tend to go hand in hand?). I recall one lesson in a telecommunications course was talking about splitting things down into smaller packets to increase speed but I believe latency increased.

I know some will object to the use of Zonealarm. My first question, does it really slow things down that much. My second question, what software can I use instead and more importantly my friend who is less computer saavy. I recall trying Norton Internet Security long ago and was not impressed, I recall my FTP server was being blocked because I chose "TCP/IP and UDP Packets" for port 21 instead of only TCP/IP packets (doesn't make sense to me, if anything I opened up too much). I like the way zone alarm will pop up a window to ask for you to give permission to new programs. The odd one I have seen you have to manually open the firewall program to give access...if I am to replace Zonealarm with something I want it to be user friendly too.

I assume a software firewall is a good idea because the router leaves ports like 80 open. Does anyone think a router on it's own is enough?

If there is a guide that answers most of my questions please let me know. I looked around briefly and most articles were to maximize speed instead of reduce latency. The other main word is wisdom I saw was not to use Zonealarm.

[YARDofSTUF]

I use a routers NAT alone for firewall, lots of things need port 80.

Find out what ur ping is, but there aint much u can do about it