Here is a table of ways things are done in macosx vs. how they are done in windows. Mostly the Ctrl key is replaced by command key. And the windows key is also replaced by the command key.
home and end page : ctrl home / ctrl end : fn left / fn right
home and end line : home / end : command left / command right OR ctrl A (stArt) / ctrl E (End)
Move backward / forward one word : ctrl left / ctrl right : option left / option right
Different windows of same application (like safari):
command+backquote (i.e. ` the key under ~) to toggle between different windows of the same application. Alt + tab like windows does not work between windows of same application.
What : Windows Explorer : Finder
delete a file : delete : command delete
rename a file: F2 : enter
open a file: enter : command down (actually go down one level)
go up one level : backspace (actually go back) : command up
The Help menu:
You can select any menu item using the help menu item added to all applications. Press command + ? (i.e. command + shift + /) to open the help menu and get focus on the search menu item. Just type in the menu item content and you will get an option to select the menu item.
Keyboard shortcuts for MonoDevelop:
Some are inspired by Emacs. Most menu options have their shortcuts mentioned which is great effort by the MonoDevelop team . The commands I used most often :
Build : command B
Debug : command return
Stop debugging : command shift return
Step Into / step Over / step oUt : Shift command I / shift command O / Shift command U
Intellisense : Control Space
Most shortcuts from here work :
http://maccork.com/2011/02/26/monodevelop-keyboard-shortcuts/
But occasionally you need to change between control and command keys. Also whenever alt is mentioned you are supposed to use the option key.
XCode:
Creating an outlet : Control click and drag from main view to assistant editor.
Additional shortcuts for Xcode development can be found here :
http://ijoshsmith.com/2010/09/18/basic-xcode-keyboard-shortcuts/