Balsa is a small and light email client written by the Gnome people. As such it has tight integration with Gnome however works quite well with other desktops or window managers.
pacman -S balsa
Balsa launches with the normal email client setup wizard that takes you through most setup. In addition there is a preferences item on the edit menu. Configuration files can be found in ~/.balsa.
One issue to which I found no good solution (unless you are running gnome) is configuring the browser to use when you click on a link in an email. I found no solution that works with my window manager: fluxbox.
The following is a dreadful hack but works:
1) click on a link in an email and note which browser it is trying to load - in my case /usr/lib/firefox/firefox.
2) Check how much of that path exists and create what is missing. I had to create /usr/lib/firefox
3) Make a soft link to your preferred browser - in my case /usr/bin/chromium
ln -s /usr/bin/chromium /usr/lib/firefox/firefox