ok, the only way i go this to work was with k-9 after 3 battery pulls. i don't know exactly why the first two didn't do it but now it seems to be working. i'm crossing my fingers that it keeps on working and not in spurts. so for people who are having problems connecting to yahoo mail via imap, DO NOT USE THE DEFAULT EMAIL APP. go download k-9. i followed the instructions here:
Motorola Droid - Setting Up Yahoo Mail IMAP | Mobile Technology Deals and Help
keep doing a battery pull if it doesn't work the first time. eventually it will. it did for me. i'll post an update regarding the stability of the connection. hope this helps someone at least.
THIS IS SOMETHING TO TRY IF YOU ARE UNABLE TO SET UP YAHOO MAIL VIA THE REGULAR APP THAT CAME WITH YOUR DROID. TRY THE NORMAL WAY FIRST BY CLICKING ON THE LINK BY THEKC ON THE POST BELOW.