In that case, go to the TextMate preferences, create a new shell variable "TEX" and set its value to "latexmk.pl".
Go back to your latex file, do typeset and view, and everything is run automatically for you.
This is all thanks to the magic of the latexmk script[1].
You might also want to create the variable TM_LATEX_ERRLVL and set it to 2, that way the script pauses when there are warnings (otherwise it only stops on fatal errors that prevent the output of a pdf).
Jeroen.