there's two things that'll do this that i know of:
http://www.foolabs.com/xpdf/
pdftotext which is a c++ open source gpl thing that is one tool / part of xpdf. its a userinterfaceless tool so compiling on os x isn't too much of a problem - there was one patch or something needed though if memory serves - i'll dig it out if you want if necessary
the other is textlightening (company name - meta projects or meta something). this gives you a cocoa service that'll convert pdfs to rtf. this on the face of it does a better job than the above, but it costs, and is a service which i'm not so keep on. also the rtf/layout/images parts will be of no use to you.
for implementing into your own code i think for licencing and logistical reasons, pdftotext maybe better - i plan on doing this myself very soon. the only thing is, it just didn't seem to convert some pdfs quite as cleanly as i'd like, but for searching, where appearence and maybe a bit too much white space here and there doesn't pose a problem at all, it would be absolutely fine for you i think. and i checked it out several months ago so it may well have been refined since maybe.
if you find or have found anything further to this i'd really appreciate if you could say here, as i'm very interested in getting access to text in pdfs.
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