Whether you want to check the memory configuration possibilities on a new Mac Pro, look up the difference between a Quadra and a Centris, or just take a stroll down Mac memory lane, the free Mactracker software can help—laden as it is with information on pretty much every piece of Apple hardware since 1984. The 5.3 update adds information on the latest Mac Pro Server and MacBook Air models, updates the 2010 MacBook Pro listing, and adds information on the Original and Maximum OS for iOS devices. Also included in this release is support for adding reminders (about expiring warranties and the like) to iCal calendars on CalDAV servers. (Free, 26.2 MB)
View Extra Audio Details in Snow Leopard
In Snow Leopard, Option-clicking the Volume icon in the menu bar displays a list of sound input and output devices. Choose one to switch to it; it's much easier than using the Sound preference pane. Also, hold Shift and click the icon to set the system volume, which is separate from the general output volume.