Here’s the full list of changes…
Interface Updates
Text shadows that match Leopard’s menubar text shadows and rounded graph corners (the text shadows are editable).
Network Extra
Copy IP buttons, PPP controls (both 10.5 only)
Electric sensors in Fans extra
The Fans extra has been renamed “Fans & Power”. It can now monitor power, current and voltage sensors on PPC and Intel Macs.
Process monitoring
added to mem extra plus updates that should fix any problems people were having, better launchcfm names.
CPU extra
We’ve added something we call “actual running time”. This is the computer uptime minus the time it’s been asleep, so the actual time it’s been actively doing something.
Swapped order of disk activity arrows - read is now on top
Added font size options for most menubar text modes
Added shadow options for most menubar text modes
Added process monitoring to memory extra
Added PPP controls to network extra (10.5 only)
Added configuration switching for network connections where applicable - vpn, modem, bluetooth (10.5)
Added option to use rounded corners on menubar graph modes
Leaner date & time dropdown
Added current read/write values as text to activity monitoring in drives extra/li>
Improved support for LaunchCFM application names in process monitoring
Fixed display bug with memory pie graph when “MEM” label was turned off
Aqua skin in date & time extra now respects the system theme (10.5)
Bug fixes with using a SMART drive as the primary temperature sensor
Improved SMART temperature monitoring
Fixed math bug in used/free mode in memory extra
Added option to disable SMART temperature monitoring when running on battery power
Added basic accessibility support to all extras
Updated Preference Pane interface
Updated clock format selector
Replaced old world clock format options with a new format selector
Added Power/Voltage/Current monitoring support to updated fans extra (now known as Fans & Power)
Updated process monitoring server
Added ability to copy ip addresses in the network extra (10.5 only)
Improved MDD temperature support
Improved Macbook Air temperature support
Network extra will now shows decimal values for KB/Kb values
Added option to to show removable media in disks extra
Improved support for vpn connections in network extra

See the full list of changes here: http://islayer.com/blog/?p=236

• Redesigned the entire pref pane interface
• Added support for 24 hour time in world clocks section
• Added support for temperature monitoring of S.M.A.R.T. capable hard drives
• Added ability to re-order world clock in preference pane
• Added activity monitor button to CPU extra (10.5 only)
• Added activity monitor button to memory extra (10.5 only)
• Added iSync button to Bluetooth extra
• Added option to show usage breakdowns in CPU graphs
• Added option to show usage breakdowns in memory graphs
• Added option to use custom graph colors in CPU extra
• Added option to use custom graph colors in memory extra
• Added option to choose if inactive memory is treated as free.
• Swap display in memory extra now displays used swap (previously just total swap)
• Added option to show week numbers in calendar
• Added option to hide/show am/pm in world clocks
• Fixed bug with time changes not being reflected in date & time extra
• Fixed bug with network filtering
• Added option to use monday as first day of week in calendar
• Fixed bug with 3rd load average value in CPU extra
• Fixed display bug with long values in network extra
• Reduced minimum size of history graphs in CPU and memory extras
• Added support for graphs in network extra
• Added ability to view other months in calendar (10.5 only)
• Redesigned calendar and world clocks in date & time extra
• Clicking on disk icons will open the drive in Finder (10.5 only)
• Fixed bug with display on 24 clock
• Added Network Utility & Internet Connect buttons to network extra (10.5 only)
• Improved 10.5 support