Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
By my opinion these terms are different in a next way:
Group delay is defined as taug(w)=d(phi(w))/d(w) - derivative of phase with respect to frequency. It defines envelope delay of narrow bandpass signal presented at frequency 'w'.
Phase delay is defined as relation tauph(w)=phi(w)/w - it defines delay of each harmonic at frequency 'w'.