Amazing HTML to PDF Converter
html-pdf-converter.com
html-pdf-converter.com
It would be useful if you want to print it exactly as it appears on screen: say as an alternative to taking a screenshot of the site and printing that.
PrinceXML has some of the best stuff in this space, targeted towards companies having the native versions of their documents be The Web, with the print version produced from that. No bullshit about 'neutral' source formats, no astronaut architecture. They share a CTO with Opera, but I don't think they share any code. -- http://www.princexml.com/overview/
It's written in Mercury -- A pure, statically type-checked Prolog with functional features -- http://ftp.mercury.cs.mu.oz.au/information/features.html
I know that might sound like an ad, but it's a really great app and I don't mind going out on a limb to say it. Its implementation of CSS3 (even the non-print parts) has yet to be matched (although browsers might be finally catching up...). Their service is top-notch. I've posted a number of questions, bugs, and feature requests on their forum and they've always been answered directly by the CEO.
http://sleep.dashnine.org/download/sleep21manual.pdf (result) and http://sleep.dashnine.org/manual (original HTML manual)
These were both produced from the same source HTML (and a lot of clever scripts).
I have nothing but good things to say about this product. It produced a nice looking result. I found its support for print specific CSS extensions made it painless to do page numbering and handle odd/even page styles differently.
This should let you print to a PDF exactly as you would print to a real printer. The only difference is that you end up with a PDF file instead of a physical printed copy. As far as CSS goes, I think that it prints websites using the style sheets that are defined for printing, just as you would expect from a real printer.
It should be really easy to add an option to firefox to do print to postscript right from the command line.
This service seems to be totally accessible using GET, so it would be easy to embed this in a Firefox extension or better yet, just create a bookmark that uses the %s replacement feature.
http://web2pdf.freepdfconvert.com/HTMLtoPDFMaster.aspx?cURL=...
As a bonus, you can take out textual watermarks in some cases, because of the Postscript being basically text.
Not sure how the quality compares, but it's certainly more convenient. (I've also never, ever used it because who wants HTML documents in a larger, less-portable form?)