At its most basic the deconvolution to the impulse response is achieved by
IR = inverseFFT(FFT(measurement)/FFT(sweep))
Where the FFT division is a point by point complex division of the FFT results. Getting from the impulse response to an RT60 figure would typically involve performing linear fits on schroeder integrals of the band-filtered impulse response. For Matlab files to do all that and more try the AcMus files:
http://www.mathworks.com/matlabcentr...bjectType=file