This applet downloads a JCAMP formatted IR spectrum from your computer (file extension .jdx or .dx)

You can download to your local hard drive some JCAMP formatted spectrum files from:

benzaldehyde
ethylbutanoate
1-pentanol
2-pentanone
phenylacetonitrile

also try Robert Badger's Polymer Science Learning Center Spectral Database from the University of Wisconsin-Stevens Point Chemistry Department