How to make LaTeXmk work with XeLaTeX and biber

As this is still very high on google:

LatexMk (since 4.31) supports the -xelatex option and auto-detects biber.

Therefore, in the fabulous world of 2015:

$ latexmk -xelatex biberedtexfile.tex

works fine.

Put

$pdflatex=q/xelatex -synctex=1 %O %S/

in the .latexmkrc file.

For Biber, look at this discussion. However the latest version of latexmk coming with TeX Live 2011 works with Biber, choosing it automatically when needed (thanks to PLK for pointing this out).

This is a really old question, but I still want to help those who are here.

Besides -xelatex option metioned by @Tommy, latexmk's doc explains $pdf_mode's usage:

If equal to 5, generate a pdf version (and an xdv version) of the document using xelatex, using the commands specified by the $xelatex and xdvipdfmx variables.

Thus, setting $pdf_mode = 5 in .latexmkrc would help.