There is no citation type for URLs, per se, in the standard BibTeX styles, though Oren Patashnik (the author of BibTeX) is believed to beconsidering developing one such for use with the long-awaited BibTeX version 1.0.
The actual information that need be available in a citation of an URL is discussed at some length in the publicly available on-line extracts of ISO 690-2; the techniques below do not satisfy all the requirements of ISO 690-2, but they offer a solution that is at least available to users of today's tools.
Until the new version of BibTeX arrives, the simplest technique is
to use the howpublished field of the standard styles' @misc
function. Of course, the strictures
about typesetting URLs still apply, so the
entry will look like:
@misc{...,
...,
howpublished = "\url{http://...}"
}
A possible alternative approach is to use BibTeX styles other than
the standard ones, that already have URL entry types.
Pre-eminent are the natbib styles (plainnat,
unsrtnat and abbrevnat). These styles are
extensions of the standard styles, principally for use with
natbib itself, but they've acquired URLs and other
"modern" entries along the way. The same author's
custom-bib is also capable of generating styles that honour
URL entries.
Another candidate is the harvard package (if its citation
styles are otherwise satisfactory for you). Harvard
bibliography styles all include a "url" field in their
specification; however, the typesetting offered is somewhat feeble
(though it does recognise and use LaTeX2HTML macros if they
are available, to create hyperlinks).
You can also acquire new BibTeX styles by use of Norman Gray's
urlbst system, which is based on a Perl script
that edits an existing BibTeX style file to produce a new
style. The new style thus generated has a webpage entry type, and
also offers support for url and lastchecked fields in the other entry
types. The Perl script comes with a set of converted
versions of the standard bibliography styles. Documentation is
distributed as LaTeX source.
Another possibility is that some conventionally-published paper, technical report (or even book) is also available on the Web. In such cases, a useful technique is something like:
@techreport{...,
...,
note = "Also available as \url{http://...}"
}
There is good reason to use the url or hyperref
packages in this context: BibTeX has a habit of splitting
lines it considers excessively long, and if there are no space
characters for it to use as 'natural' breakpoints, BibTeX will
insert a comment ('%') character ... which
is an acceptable character in an URL. Any current version of the
url or hyperref package detects this
"%-end-of-line" structure in its argument, and
removes it.
This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=citeURL