iZotope Vinyl is a free app (requires registration) which resamples your audio as if it were being played on a record player. From the site:
The ultimate lo-fi weapon, iZotope Vinyl uses 64-bit processing and advanced filtering, modeling and resampling to create authentic “vinyl” simulation, as if the audio was a record being played on a record player.
And with Vinyl 1.7, we now provide support for Mac OS X as well as Windows. This adds the MAS and Audio Unit formats to our list which already includes HTDM, RTAS, AudioSuite, VST, and DirectX.