Yeah, I originally posted another work around to check your sprint email with the Instinct, but since, I have talked to someone from Sprint and got the correct info to set it up. The Incoming server is pop.sprintpcs.com, and the outgoing is smtp.sprintpcs.com. Hopefully I'm allowed to post that here since it was provided to me by Sprint, though I did go through a different channel to get it from Sprint. In the past, Sprint has been reluctant to allow access to email in this manner, its nice to see that they are letting us now.
When I try and set mine up it says check your username and password. I used my sprint email addy and the password I have set up for my account but its not working
If you have been using SprintPCS.com email before, you should be able to continue using the exising ID and Password you created a while ago. If that does not work, then you need to reach out to customer care - click the 'Chat with Sprint' button.
If you want to start using SprintPCS.com email, I suggest you look to GMail. We are working on changing the PCSMail system and currently it is not accepting new account requests.