Chrome's implementation is special because it uses the built-in PDF plugin to convert the page you want to print into a PDF file. There's no special "print preview" option: when you click "print", Chrome opens a new tab that shows some of the options from the native print dialog and a preview pane.
Chrome generates a PDF file every time you click "print" and when you change printing settings and you can save the file by selecting "Print to PDF" from the "Destination" drop-down. Unfortunately, Chrome's PDF files are huge (the file generated for Google's homepage has almost 1 MB). Google managed to reduce the performance penalty of generating PDF files and now print preview is pretty fast, on par with Internet Explorer 9.
To open the native printing dialog, click "Advanced". You'll be able to change printer settings, add a new printer or print selected text. If you disable the built-in PDF plugin, Chrome will show an error message instead of the preview and you'll only be able to print a page using the native dialog. That's an important flaw that needs to be addressed before releasing the stable version.
Chrome's tabbed printing page doesn't integrate with Google Cloud Print yet, but this feature will be available in the future. Google plans to add many other missing features: ability to adjust headers, footers and margins, shrink/expand to fit page, integration with Google Docs, a search box for printers, location-aware printer selection, syncing print preview settings to the native dialog.
For now, print preview only works in Chrome 13 for Windows and Linux. If you don't want to wait until the first stable release that supports print preview, you can install Chrome 13 Beta. Another option is to install Chrome 14 Canary and run it side by side with the stable release.