I am about to install Solaris9 on a sun server. I have no mouse or keyboard for the server. I do however, have a slackware server sitting right next to it. Is it possible to connect the to machines together using a null modem cable (the serial ports) and then somehow console into the sun machine from the slackware machine? I have never installed Solaris before... so its a bit new to me. I have the Solaris9 CDs... just looking for the best way to install without a monitor or keyboard.

If anybody can offer some suggestions, I would appreciate it. Thank you.

Sure, for sparc everything will automatically come through the serial connection when there's no kb/mouse. I've never done a serial connection from a linux client so all i can refer you is:
http://rtfm.dyndns.info/tips/2000/06/13/34.shtml
then you need a way to send a break command (there's a message in this forum regarding that) to get the ok prompt; then do "boot cdrom"