I would like to keep my old kernel along with 2.6.0
in /boot for now.

My question is this:

When I move the 2.6.0 kernel to /boot, is it important
also to copy the new .config and System.map into /boot?

Not really.

It's not a bad idea, though. Some programs I think require it and it only costs you 2 minutes at most. Its a good idea to call them something like "Sytem.map.<kernel version>" and then make a symlink to the one you use most called "System.map". Same for the config file.

Adding to what the other posters replied I'd say to:

$cp linux-2.6.0/.config /boot/config-2.6.0

For documentation's sake.

thanks for the info, guys.

The .config file isn't necessary as it is not used for kernel booting operation.
System.map is necessary to klogd to "collect" messages from the kernel while booting.
They are given to ksyslogd that prints those messages to the console.
System.map is also used by some emulators as they use those infos to work.
klogd search by default in three directory his suitable System.map.
They are /boot, / , /usr/src/linux-x.x.xx (not sure in this order).
klogd has versioning features as well, so if you rename System.map to System.map-x.x.xx,
it is able to find out the proper System.map.
Simply cp ....../src/linux-x.x.xx /boot/System.map-x.x.xx
Ciao

That's good to know, urka58, thank you. I checked the
man page of klogd. The order is

/boot/System.map
/System.map
/usr/src/linux/System.map