Evolution is a GNOME mail client it supports IMAP, Microsoft Exchange Server and Novell GroupWise. It also has a calender function that supports vcal,csv, google calendar and many more. You can also organise your contacts, tasks and memo's with Evolution.
This is the setup for a standard IMAP mail adress. Go to Edit -> Preferences -> Mail Accounts. Add a mail account insert your Name and real email adress. Then click 'forward' here you are going to select the server type, this is IMAP. Now fill in the textbox server, for the server adress and username. For the rest of the options just follow the wizard. It is very easy, if you get stuck read this guide .
Setting up gmail for evolution is very easy. Go to Edit -> Preferences -> Mail Accounts and make a mail account. For your Email Adress: <username>@gmail.com . Now press forward Use this configuration Server type: POP Server: pop.gmail.com Username: <username>@gmail.com Use Secure Connecetion: SSL encryption Authenthication Type: password
Now go to the next step:
Optionally fill in automatically check for new mail every ** minutes. The rest is user specific.
Go to the next Step
Server type: SMTP Server: smtp.gmail.com Flag: server requires authentication Use Secure Connection: SSL Fill in Username: <username>@gmail.com
You are now finished with configuring evolution for gmail. Just hit Send/ Receive in the main screen and wait for new mail. If it still didn't work, go to this link 
You can use your gmail calendar in evolution here's how:
Go to your calendar in your browser. Click on manage calendars -> the click on the calendar you want to add -> In the Private URL section copy the URL of ICAL (green button).
Now go to Evolution. Click on file -> new -> calendar . In the 'new calendar dialog box' select type: On The Web. You can fill in your own calendar name Then Copy the URL to the URL field
Now you will see your google calendar in your calendar view in Evolution by the name you gave it in the Name field.