If yahoo only allows pop3, then I dont think that this will work, but might be worth some investigation by someone more familiar.
goto
and open a free account. You will actually be setting up an email account. Write down the server settings (for activesync) which will look like "mobile.exchange.mail2web.com".
go to your email and try to find a setting for forwarding Email. On Gmail, you can go to filter and then set up a filter and set a forwarding address, "youraccountname@mail2web.com". On Gmail you can also set a filter so that you can have less imporant things filtered out, before forwarding.
On your device, get into activesync and hit Menu->configure server
You should start with a screen that is for the server address. This is where you put in, from above, "mobile.exchange.mail2web.com". I dont have the encryption checked (from my understanding many work type email programs and access will require this. I dont use this for my employer email, they get enough out of me when I am there!)
type in your user name (yoursuername@mail2web.com) and password. I left domain blank, and checked save password (that way it can run automatically) Choose the settings that you want synced.
I think that should just about cover it....I might have missed a little thing here or there but for hte device configuration, i looked at my device as i was typing so that should all be right.
HTH
--------- New Post Merged on 10/3/2009 at 09:22:13 --------
I believe that you can also accomplish much of the activesync settings by setting up a new Outlook account on your device. If I remember correctly it will go to the same area.