Install the latest version (7.0) of Adobe Reader, known in a past life as Acrobat Reader, and it will also install a Safari plugin that enables you to view PDF files directly in a Safari web browser window (http://www.adobe.com/products/acrobat/readstep2.html). This saves a bunch of time over downloading the PDF to disk and then launching Acrobat. This is one feature that was handy on a PC, and while there was a third-party plug-in floating around that does this, it's very nice that Adobe now provides that functionality out of the box (click the screenshot for a larger version).
This has, obviously, been around since Reader 7.0 came out, but with the stability of OS X, it was only today when I accidentally quit Safari and then had to relaunch it that it picked up the newly installed Internet Plugin that's installed in /Library -> Internet Plugins -> AdobePDFViewer.plugin.
[rob griffiths adds: I hadn't even downloaded Reader 7 yet; after installing it and testing the PDF plug-in, I must admit that Adobe's done a really nice job with it -- there's a page browser sidebar, searchability, comments and attachments show up, selection and rotation tools, and full zoom control. Schubert-IT's PDF Browser Plug-in still has a role to play, though, as the Adobe solution seems to only work in Safari...]
http://www.schubert-it.com/pluginpdf/
UPDATE:
Since this subject has attracted a fair bit of attention, and quite a bit of "Schubert vs. Adobe" discussion, I took the time to do a head-to-head comparison of the two plug-ins.
| Feature Description |
Schubert
|
Adobe
|
| Save |
Y
|
Y
|
|
Y
|
Y
|
|
|
N
|
Y
|
|
| Search |
N
|
Y
|
| Search Options |
N/A
|
Whole words only, case sensitive, include bookmarks, include comments, match exact word or phrase or match any words, proximity, stemming
|
| Text Selection/copy |
N
|
Y
|
| Graphic Clipping |
N
|
Y
|
| Zoom Options |
+ and ? buttons
|
14 specific sizes, + and ? buttons, fit page, actual size, fit width, fit visible
|
| Fit Page Vertical |
N
|
Y
|
| Fit Page Horizontal |
N
|
Y
|
| Fit Whole Page |
N
|
Y
|
| Rotate Page |
Y
|
Y
|
| Spell check |
N
|
Y (comments and form fields)
|
| Form Support |
N (data can be entered but not saved)
|
Y
|
| Undo Field Changes |
N/A
|
Y
|
| Browsers |
Most
|
Safari Only
|
| Hide Toolbars |
Y
|
Y
|
| Viewing Options |
Individual, Facing, Continuous
|
Single page, Continuous, Continuous Facing, Facing
|
| View One Page at a Time |
N
|
Y
|
| Show Attachments |
N
|
Y
|
| Thumbnail Page Browser |
N
|
Y
|
| Jump to Specific Pages |
N
|
Y
|
| Jump a Page at a Time |
Y
|
Y
|
| View Comments |
Y
|
Y
|
| View Comments as Text |
N
|
Y
|
| Search Comments |
N
|
Y
|
| Quick 'Open With Viewer' Access |
Y
|
N
|
| Table of Contents Button [Note 1] |
Y
|
N
|
[Note 1 I couldn't find a PDF online with a table of contents with which to test this feature, so all I can state is that Schubert has a button for it, and Adobe does not. It may very well work fine in both plug-ins, but I don't have a viable test document to check them with.]
http://www.macosxhints.com/article.php?story=20050118025943971