No, you can't use any Sigma, as Sigmas are made for the various different lens mounts - Canon EF, Nikon F, Pentax K, Minolta/Sony A, and Four-Thirds (the one used by Olympus)... you can only use the ones designed for your lens mount (Four Thirds).
According to the Sigma website, the Sigma lenses currently available for the Four Thirds mount are the following... 18-50mm F2.8 EX DC Macro. 18-50mm F3.5-5.6 DC. 50-500mmF4-6.3 EX DG APO. 135-400mm F4.5-5.6 DG APO. 300-800mm F5.6 EX DG. 24mm F1.8 EX. 30mm F1.4 EX DC HSM. 105mm F2.8 EX DG Macro. 150mm F2.8 EX DG APO Macro.
Something I missed before: the Four Thirds website lists all the compatible lenses made by Panasonic (Leica), Olympus and Sigma. Hope that helps.