Hello Cindu,
The logs are at /var/log/dcpumon/ location by year and month, so /var/log/dcpumon/2011/Feb/ would contain the February files. These are then in there by day.
They also have top process logs at /var/log/dcpumon/toplog.# location. These only contain the top information for the last 30 minutes of the server for every 5 minutes, which is what the Daily Process Logs use to gauge the activity.
Thanks.