UIBarButtonItem image with the "creation" button

I'm new to the iPhone SDK and I wonder, where I get some standard buttons, that a lot of applications use. I wanted to have that button:

http://4.bp.blogspot.com/_fAv06gZ6FPU/S开发者_JAVA百科umCCleuwpI/AAAAAAAAAFs/0mtPapm8EFg/s1600-h/Screen+shot+2009-10-29+at+11.47.20.png

in an UIToolbar. Any advices please? :-)

Thanks in advance...

[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCompose target:myTarget action:mySelector];