Code:
$ cat 24hr.awk
BEGIN { FS=","; OFS="," }
{ # Split "Nov 2 2011 12:01AM" into A[1]="Nov", A[2]="2", A[3]="2011", A[4]="12:01AM"
split($1, A, " ");
# Split "12:01AM" into B[1]="12", B[2]="01AM"
split(A[4], B, ":");
HR=B[1];
MIN=substr(B[2], 0, 2); # Get "01" out of "01AM"
AM=substr(B[2], 3); # Get "AM" out of "01AM"
HR %= 12;
if(AM == "PM") HR+=12;
# Put the data we want back into first field the way we want it.
$1=sprintf("%s %s %s %d:%02d", A[1], A[2], A[3], HR, MIN);
} 1 # Always print the entire line.
$ awk -f 24hr.awk < data
Nov 2 2011 0:01,52893,420,1,4,0,52834,4,1208,67664942,603459924403.0,1,150054,1208,3
Nov 2 2011 17:16,52127,420,1,4,0,52122,4,1429,55943831,603459924406.0,1,150054,1429,3
$