[Orgmode] Effort Estimates

[R C]

Hi,
 I am new to using org-mode. I have read the section on effort estimates, but I 
am not quite clear on the implementation. I am particularly interested  in 
using org-mode to compare estimated times to clocked times for tasks, and in 
getting a summary of the estimated work effort for each day in agenda view. I 
would appreciate it if anyone using org-mode for these purposes would be 
willing to provide specifics of their implementation.
Thanks.
Recif