You will need to install cups on the linux system. You will need a print driver for the printer. You did not state what printer, make model, etc. To find out if the printer is supported in linux, go here -->http://www.linuxfoundation.org/colla...s/openprinting
Look in the database for the make and model you have. Install the print driver.
In cups, add a remote printer. To access cups, from a web browser, enter, http://localhost:631
to connect to cups. Add the printer with the driver you installed.
The vista system has to have the printer shared, it is now since you can print from your sys A. Beyond that, you can not use 'homegropup' Simply put, it will not work with linux. You have to set up windows sharing on vista as you would have on an XP system. That will work. There are a ton of hits if you google 'homegroup' and linux.
That is the short version. Post any specific questions you may have, with as much detail as you know.