If it's not available in your Linux distribution try: Serial Software for Linux software for the serial ports including getty and port monitors. Serial Communications for communication programs.
irqtune will give serial port interrupts higher priority to improve performance. Using hdparm for hard-disk tuning may help some more.
Low-Level Terminal Interface part of "GNU C Library Reference manual" (in libc (or glibc) docs package). It covers the detailed meaning of "stty" commands, etc.
Modem-HOWTO: modems on the serial port
PPP-HOWTO: help with PPP (using a modem on the serial port)
Printing-HOWTO: for setting up a serial printer
Serial-Programming-HOWTO: for some aspects of serial-port programming
Text-Terminal-HOWTO: how they work and how to install and configure
UPS-HOWTO: setting up UPS sensors connected to your serial port
The Linux serial mailing list. To join, send email to majordomo@vger.kernel.org, with ``subscribe linux-serial'' in the message body. If you send ``help'' in the message body, you get a help message. The server also serves many other Linux lists. Send the ``lists'' command for a list of mailing lists.
