we just made another bicycle parking rack from old unusable bike frames, and donated it to a neighborhood park. they loved it.
one recipe, of the several we are trying:
1- on a one-piece crank bicycle, strip frame to almost bare, especially bottom bracket shell
2- punch out bottom bracket cups
3- repeat with 2 more similar bicycles
just posted a picture- click on link that is listed about 7 pictures down at: http://freecycles.org/pedaltechnology.html
this new style is much more sturdy than the inverted frame, stem into the seat post method we had been using.
-Bob g. free cycles.
Another thought - be careful with police department bike dumps. They
sometimes be good, but the last police dept that "donated" us bikes
literally gave us a week's worth of work scrapping out junk for pretty much
nothing that was useful.