envelope is written for a Laserjet 5L printer, using Ghostscript.
It is a nice example of using a shell-script to output a (postscript) file. This can probably be used on other printers, if you hack at it a little. Do so at your (p)leasure.
Edit the script to include your own name.
As root, copy the file to /usr/local/bin, and give it execute permissions. (mode 755).
Give the command "envelope filename.ps". Fill in the address. Print the postscript file to the LaserJet 5L, using Ghostscript. Put a 11 x 22 cm envelope in the envelope tray first.