I'm writing a grant application and space is at a premium. I want LaTeX to print my references section without line breaks, so
References
[1]
[2]
[3]
becomes
References
[1], [2], [3]
I don't think the exact references style is too important (this is NSF), but I can't seem to find any bibliography style that will do this.
I would definitely consider the advice from Dirk Eddelbuettel, first. However, reformatting the bibliography seems to be something of a black art, but there are two major methods for doing so: custom-bib and biblatex. Custom-bib operates by interrogating you as to the myriad features you might possibly want to use. I've tried to use custom-bib in the past with little success, but others have used it successfully.
Biblatex, however, uses latex commands directly within the document itself (or, style file) to generate the style. Internally, it divides each bib entry into blocks and units with settable punctuation between them (via \newblockpunct and \newunitpunct, respectively), and usually a block is an entire entry. It should be noted that biblatex is still in beta testing, so it may still have some quirks. Also, be sure to check the prerequisites for running it. As of this point, I have not used it, but if the documentation is at all accurate, I intend to.
Edit: I looked at the style file again, and it appears that biblatex is implementing the bibliography environment as a list. So, to achieve what you are looking for, you would use paralist instead. You may be able to renew thebibliography environment yourself without using biblatex, but you may have to dig through your bst file to figure out what formatting commands are used. The method with biblatex just seems easier.