I suspect most likely you get your email from your internet service provider (ISP). If so, you almost for sure use POP. You can either check the email settings on your computer or check with your ISP if you are not sure. The same settings would be set on your iPod like the last poster mentioned. Now one thing, is that when you download your email to your iPod, you will not also be able to download it to your computer as it will move from your ISP's server to your ipod. Or if you check your email on your computer and download it, it will not be downloaded to our iPod since you already retrieved it to your computer. There are some ways around this, let me know if you need to know how you may do this.
If on the other hand your email is your company email, they most likely have an Exchange email server. Then you will need to get with your administrator and get some additional settings and here you use IMAP. He will need to open port 993 (IMAPS - Secure) on the company router and provide you with the server name etc.
Hope this helps a little more.
mrmmd