EMail practices

After hearing Grover talk about gmail and how he is using this for all his email, I have decided to try this out for myself. I am a Macintosh user by preference and enjoy using Leopard's email client. I am in the process of testing:

• forwarding all my JMU email to my Google mail account. (I have consistently run out of space with my JMU account and hopefully this will allow me to keep email as long as I want to)
• I still wish to use the Leopard (Apple) email client so I am testing my configurations so that I can send mail either from my JMU address or from my Gmail account using this email client.
• I am unclear about where copies of my sent-mail messages go when I use my JMU account - I suspect these still remain on the JMU server (can anyone clarify this?). If this is the case I will most likely will have to move these over manually to my gmail account.
  

Well I will see how my email adventures go this week and then decide if this practice is worth continuing for me.