The easiest way I've found to install stuff is with Fink.
None of this is original. I just compiled it to save you the considerable trouble.
Update: This seems to have been fixed some time in mid 2006.
I was getting truly abysmal tcp performance on my Powerbook until I turned off delayed acks:
sysctl -w net.inet.tcp.newreno=1 sysctl -w net.inet.tcp.delayed_ack=0
You can put this in /etc/rc.local. I think you could just put something in /etc/sysctl.conf but I haven't tried that, and I don't know if it will get blown away when you update the OS.
This is necessary because Mac OS has the "Stretch ACK violation" bug as described on page 40 of RFC 2525. Mac OS apparently inherited this bug from FreeBSD, but not the fix, which went in to FreeBSD (and the other BSDs) many years ago. Turning off delayed acks is not a good solution but is about the only thing an ordinary user can do. This is a well known bug in Mac OS, and why they have not fixed it is unclear. It has been discussed on various tcp/ip mailing lists as far back as 1997.
Most PCI USB adapters do not work in any Mac. I wasted a fair amount of time and money finding this out. Some adapters even claim to be Mac compatible but they are not. More about this problem at the macosxhints Forums.
I couldn't get cdrecord to work until I specified dev=IODVDServices, which is not even listed by dev=help. Apparently you have to use IODVDServices if your drive offers any DVD services at all, even if you are just burning a cd. There is more info at UNIX CD BURNING.
If you don't need all the fancy options of cdrecord, the easy way to burn a cd from an ISO 9660 image is just to use Disk Utility.
Jim Rees