Add user on old database with password

<div align="left"><font face="Arial"><span style="font-size:10pt">Hi All</span></font></div><div align="left"><br
/></div><divalign="left"><font face="Arial"><span style="font-size:10pt">i am new on Postgresql7.3. so please
help.</span></font></div><divalign="left"><br /></div><div align="left"><font face="Arial"><span
style="font-size:10pt">ihave create one(ICPS) Database  with Postgre user and password is NULL.</span></font></div><div
align="left"><fontface="Arial"><span style="font-size:10pt">now i want to</span></font></div><div align="left"><font
face="Arial"><spanstyle="font-size:10pt">1) create one user with password and all Grant on Database. it is a admin
user</span></font></div><divalign="left"><font face="Arial"><span style="font-size:10pt">2) i want to add password to
postgresuser.</span></font></div><div align="left"><br /></div><div align="left"><font face="Arial"><span
style="font-size:10pt">PleaseHelp</span></font></div><div align="left"><br /></div><div align="left"><font
face="Arial"><spanstyle="font-size:10pt">Ramesh Patel</span></font></div><div align="left"><font face="Arial"><span
style="font-size:10pt">ramesh@banas.guj.nic.in</span></font></div><divalign="left"></div>