I used to switch windows using win+1..9 on windows 7. Now switching to mac, i wonder if is there any equivalent feature in snow leopard? Or maybe there exist some third-party application support that?
There are quite a few commands which let you do this in Mac OS X:
Cmd+Tab for switching applications
Cmd+` for switching windows within applications
F3/F9 for Exposé (shows all windows in a graphical way, on trackpads you can do a 4-finger swipe down)
F10 for showing windows of a specific application in Exposé
F11 for showing desktop and shoving all other windows to the side, on a trackpad its 4 finger swipe up
There is also Spaces which is like having multiple desktops, where you can switch to and fro. You can enable it in the
Exposé & Spaces prefrence pane in System Preferences and suit the keyboard shortcuts to you liking
I don't think that either Expose or Spaces quite do the job well. I bought and use Witch, from Many Tricks. It allows you to switch not only between applications (as you would using Command-Tab), but also between different windows of each application.
I like the way that Witch gives me preview windows for each application's windows, and that it is fully Spaces-aware. It has a ridiculous amount of options to fine-tune its behavior to your liking. Well worth the $14 US for me.
I haven't used Win7 but I guess you are asking about Expose. F9 key or Four finger swipe down on trackpad that shows all the window and select the one you want to switch to.
you may find the F10 key useful if you want to see all windows of an application.
Edit: The keyboard shortcuts are from external standard keyboard. Apple keyboards have special keys, F3 & Cmd + F3 or Fn + F3
Optimal Layout, an app I developed, lets you start typing in the name of the app/window/tab you want to switch to - this is a really fast way to switch windows if you are a touch typist.
If you want a quick simple way of switching apps from a list, try out contexts, reminds me of dmenu from Linux.