Android has a built in email client application that you can use as your email client. If you have an email account on Google Apps, you can configure this email client to access your email apps account.
NB: The screenshots below using Android 2.1 (Eclair) running on Samsung Galaxy Spica.
- Enable IMAP access in your email apps settings (Settings -> Forwarding and POP/IMAP)
- Open email application on your android phone
- On Set up email screen, enter your full email apps address and password then press Next
- Choose IMAP on the next screen
- On Incoming server settings screen, enter your full email apps address and password, imap.gmail.com on Imap server, 993 on Port and SSL on Security type than press Next
- On Outgoing server settings screen, enter smtp.gmail.com on SMTP Server, 465 on Port and SSL on Security type than press Next
- On Account options screen, choose your prefered email checking frequency and notification option than press Next
- Give your account a name and displayed name on outgoing messages then press Done
- Email client will download your messages, you can configure more options by pressing the menu button.