Vista - Painfully Slow Printing

We are home networked with an XP computer connected to the printer and the
router. There are two Vista machines connected wirelessly. Suddenly, in the
last week or so, the Vista machines began to experience extreme wait times
when accessing the printer. I watched one today and it started just in a
wait state, then it told me it was background printing the document. The
computer slowed so much that WORD told me it was "not responding", yet it was
apparently still building the background print. Eventually, I got the print
queue to display, it finally showed a 34.7 KB document with the name of the
user. That flashed through the queue and was immediately replaced with a 2.4
MB file that showed the "owner" as "guest". At that point the document
FINALLY printed. This all took in excess of 5 minutes to occur.
Thanks for any help you can offer.
Kim