John V. Scialli got the Astronomical Society to name an asteroid for Zappa. Read all about the Asteroid Zappafrank at the Black Page! Asteroid page.
Take a look at starchart #1 (gzipped PostScript, 21K) and starchart #2 (gzipped PostScript, 31K) which plot the track of the minor planet (or asteroid), Zappafrank (#3834, 1980 JE), from mid-1994 to mid-1995.
To see Zappafrank you'll need to use a telescope or large binoculars under a dark sky, away from city lights. Observe the region you think contains Zappafrank and draw the positions of the stars you see. If you look again after a period of a few days, the "star" that has moved will be the minor planet.
The week Zappa died, alt.fan.frank-zappa (GIF, 107K) was overwhelmed by reactions from fans on his death. All of these are saved in the FZ Usenet Tribute File (text, 613K)
Zappa was also inducted to the Rock 'n' Roll Hall of Fame. Strange enough, Lou Reed was chosen to induct Frank into the Hall of Fame. This Newspaper article with comments from Gail tells the story.
Many people have given their computers Zappa-like names.
The animation series Duckman was using a lot of Zappa tunes in their first season as a tribute to Zappa. Todd Yvega, who used to be Zappa's computer assistant, is responsible for Duckman's music and Dweezil does the voice of Ajax.
Other tributes include a large number of Zappa Web sites, MIDI files and Guitar Tablatures.
Intel has given one of their Motherboards the codename Zappa.