|You could configure Hotmail and Gmail as POP, but you should take into account that all messages on the server will be downloaded to your pc and will be deleted from the server. Meaning, you won't be able to restore them if something happens to your PC and you won't be able to view those messages on other devices other than the one you configured for POP.|
IMAP is a good alternative where you can access your messages on several devices and keep them in sync.
As for GMX, I'm afraid I'm not familiar with it, but I'm sure it provides support for POP and/or IMAP
For the settings themselves, visit the support pages of each provider.
"I'm tired. But then again I'm so hungry I can't sleep. But what's the point of eating if your sleepy?" - Sniff, The Moomins.