Time warner mail through Yahoo on iphone?

I guess that time warner roadrunner mail doesnt work with iphones,but I thought I read somewhere that you can somehow have your road runner mail automatic forward to my yahoo address which then would alert me as if it were coming from yahoo? Im not sure if I misunderstood what I read or if this can be done,if so can someone tell me how to go about doing this?
I was also wondering if its possible to add custom sounds to alert you when mail comes in,right now I get a bell and a vibrate but there are no custom option that I see and only like 4 choices of email alert sounds?

 

Thanks I got the forwarding thing done,But what about the custom email sound. I got dr evil saying "You got freakin mail" That would be cool if I can get that to work when a email comes in