My Non Disclosure Agreement (NDA) with Apple precludes me from revealing proprietary detail, but because most, if not all, of this is posted elsewhere and it is commonly available, I have no problems with confirming the following. Still, please don’t quote me.
In addition to those things Steve has already announced and are posted at the Apple site:
1. Leopard no longer "officially" supports OS 9 or earlier. Legacy apps may still work, but Apple just won’t support them. You can however, install OS 9 on a separate volume and run Classic from there (even on Intel machines).
2. During the Leopard install, you are given the option to create specific partitioning to accommodate M$ Vista and Linux, a la Bootcamp. Reformatting your HD is not required. Depending on your processor and RAM, all OSs can run simultaneously & independently. A (minimum) 150 GB HD is required (250 GB is recommended), and 2 GB RAM (minimum) should you wish to run more than one OS. Dual processors are required (quad preferred) for optimum performance, though this may change in 10.5.1 or 10.5.2. To the extent the app allows it, you can drag and drop between OSs
3. DiskWarrior (in lieu of TechTool) will be bundled with 10.5 if one chooses Apple Care or extends their current Apple Care contract. I don’t know the pricing or specific details, though Apple Care for older machines will increase significantly with the machine’s age. Machines over 6 years old (from date of mfgr.) are not eligible.
4. Safari will include editable Helpers (finally). Safari Tabs can be assigned colors. Safari will be about 37% faster (YMMV). The default for Safari bookmarks will now be alphabetical by folder (finally). Safari will include configurable parental controls (for those who want configured parents). Safari will now import Firefox and Camino bookmarks. Also, there are 12 new Safari “skins”.
5. The Dock will be much different. One new feature is that as icons are added, they will automatically migrate/expand around the screen as needed (or, you can reduce the size of the icons as presently done). Also, multiple docks are an option as is the amount/speed of “bounce” desired in those dock apps launching or needing your attention. There is an accompanying bounce sound, a boing-boing sort of thing.
6. Hooks are built-in to support an Apple PDA, but I can say no more. Think of the iPhone on steroids.
7. All Metadata will be editable.
8. You can have 3 ‘Finder’ windows open simultaneously, much like having 3 displays, all running different applications or OS’s. If networked, any 3 computers can be displayed. Depending on the function/application, you can even Drag & Drop between displays. Password or Admin. privileges are required. (see #2 above).
9. Widgets can run on any or all of your open windows, similar to the way Stickies can be placed anywhere.
10. Terminal has balloons that will appear with alerts/warning notes should you wish to do something that you will (later) wish you hadn’t.
11. Mail, Address Book, iCal, iSight, and iChat will become one integrated application, much like Entourage (but better). Included is a customizable Auto Responder and voice activated dialing via numbers or Address Book names. You will be able to automatically send email & initiate iSight meetings, etc. that are linked/pegged to specific calendar events. This feature is called AutoPilot (see #6 above).
12. Voice recognition/security has returned as an option (see #6 above). Note: Use with caution. I am still not certain this will make the final release (it’s still a bit buggy); perhaps delayed until 10.5.1.
13. An across the board speed increase of 35 - 40%. YMMV.
14. Font, Printer, and User Preference (.plist) verify & repair routines are built-in and are schedulable.
15. Sherlock has been eliminated (use Widgets instead).
16. When Repairing Permissions, you will have the opportunity to save and print the results.
17. Airport (Extreme only) will notify you via the airport icon flashing in the menu bar if your signal is being hijacked or used by anyone other than you authorized.
18. Startups, Restarts, & User Switching will be exactly as the User left the machine; open apps, window positions, network connections, etc. will all be reestablished.
19. Bundled with Leopard is a small app called “TrashBack”, a program to recover deleted files. Of course, the sooner one uses it after trashing the better.
20. Numerous (other) bug fixes, including a totally rewritten Spotlight.
21. Your Home folder can no longer be moved or modified without root privileges.
Leopard will be announced June 11th at the WWDC and be available for shipment at that time (and I can hardly wait for the final version).