Well then you have two options. you can use the built in HTC program to configure and retrieve those accounts, or you can set the accounts to automatically forward to your gmail.
To set up the E-Mail program HTC bundles follow these instructions taken from the HTC website:
"From the All Programs screen, tap Mail. If this is the first email account, follow the on-screen prompts to set up the desired type of email. If this is not the first email account, tap Menu > More > New account and follow the on-screen prompts. "
Good Luck!