i had this very same question, posed it over at XDA and got some great responses:
http://forum.xda-developers.com/showthread.php?t=365334
UltimateLauncher is the best, its what i use currently, here is a video of someone using it:
http://www.youtube.com/watch?v=-bNtHCOpZlQ
as you can see, swiping switches the today screen. currently I have 3 tabs on mine, one for home/calendar, one for weatherpanel, and one for common shortcuts. you can change the animation for switching between slides as well.