Official Gmail Blog: Sync your inbox across devices with free IMAP
if you have read the earlier post on IMAP/POP you can skip this.
"how to use gmail free IMAP with Microsoft outlook"
1. log in gmail
2.go to settings
3.enter the tab "forwarding and POP/IMAP "
4. enable IMAP
6. go to outlook
7.click tools>add an email account>next>select IMAP>fill your email&name
8. in the incomming server enter pop.gmail.com and in outgoing enter smtp.gmail.com
9.click more settings>general tab>type gmail under mail account
10.click outgoing server>select my outgoing server need authentication>repeat same for incoming
11.click advanced tab>under server port number,change outgoing server to 465 click ok>finish
12.you can also run test to check connection.
remember do not select secure password authentication.