Per a 2004 beat map that I have, from south to north, with the city limits as any unmentioned border:
11 & 12 beats are between Northern and Olive Aves
21 & 22 beats are between Olive Ave and Grand Ave
31 & 32 beats are between Grand Ave and Cactus Rd
41 & 42 beats are from Cactus to Thunderbird Rds
51 & 52 beats are from Thunderbird to Bell Rds
61 & 62 beats are from Bell to Beardsley Rds
71 & 72 beats are from Beardsley to Pinnacle Peak Rds
81& 82 beats are everything else north of Pinnacle Peak Rd
90 beat is south of Lone Mountain Rd, between about 107th Ave and whatever the western city limit is.
John
Peoria