A: You have not downloaded the Snow Leopard version of Quicksilver.
A:Not all windows allow resizing, this is something that the developer of the application has control over. Sometimes updating your application will either break or enable resizing of windows within an application.
A: This may change with updates but a few common apps that work are: Finder, Safari, Firefox (seems to change back and forth with each update), Camino, OmniWeb, Google Chrome, Opera, iTunes, iChat, Soundtrack Pro, Apple Remote Desktop, GarageBand, iWeb, iCal, iPhoto, Numbers, Pages, Keynote, TextEdit, Youjimbo, Apple Mail, MS Excel, MS MS Word (on first open document and then when closed the next opened document), Entourage, Automator, Address Book, Script Editor, Camtasia, Delicious Library, Compressor, Disk Inventory X, Dupin, QuickTime Player, PT Plug in Manager, Script Debugger, Real Player, VLC Player
You can even resize windows you may not want to resize like System Preferences or plug-in windows in Logic or apps like iVeZeen
A: Waveburner, Logic Pro, Pro Tools, MainStage, Cubase, Digital Performer, Nuendo, Ableton Live, Thunderbird, OpenOffice, iDVD, Preview (generaly it doesn't work but it depends on the file it opens), Adobe Reader, Adobe Media Player, Adobe Image Ready, PhotoShop, Dreamweaver, Fireworks, Amazing Slow Downer (not needed), Algebrator, Chess, Dictionary, Cyberduck, Diskring, DivX Player, Internet Explorer (and why are you still using this browser?), Flock, DVD Player, Docks, Google Earth, ScreenFlow, Skitch, iShowU HD, Apimac Timer, Mac Tracker, Mac Help Writer, Mac Update Desktop, Skype, SoftChalk Lesson Builder, Mental Case, Make Ref Movie, MIDI Monitor, Money, Stickies, Spear, Transcribe!, Tube TV, Version Tracker Pro, VTC Air Player, Wondershare YouTube Downloader
The following apps don't work with SP Resize but it probably doesn't really matter with these apps.
Amazing Slow Downer, PhotoBooth, BWAV Reader, Calculator, Chimoo Timer, iMovie, Display ConfigX, HandBrake, Reason, Stuffit Expander, Sooper Looper, VM Ware Fusion (depends on what you are doing but OS doesn't resize)
A: SP Resize is intended to be run and then closed. Close SP Resize and reopen it and the window sizes will reappear. Hey why not open it with Quicksilver?!