How to configure Sendmail

dear all

i am having redhat 7.1. i want to setup sendmail server. i want full help from the base. can any one help me. i am having few doubts too.

1. is sendmail can be used for intranet mail purpose? if yes, what mail client i can use. how to configure the same?

2. for eg i am having e-mail id in my intranet environment. is this id can receive mail from internet, in other words can i send mail to that id. if yes, what is the requirements. now i am using internet through proxy.

pls. give solution to me, i want to setup this in our office. i want detailed information.

thanks in advance

sakthi