Alright well I was able to get Yahoo working doing the following.

Install winetricks first and follow the steps in the tips section then come back here.

Here is a list of dlls you need they all should be in winetricks, whatever you can't find in winetricks, look in your ies4linux wine system32 directory

Yahoo might complain that riched20 is missing and not startup, if that is the case, take the riched20 from your wine directory and put it with yahoo. The audio and video does not work, I tried webcam and the webcam would turn and back off, it is probably just not supported with wine yet because I didn't get any errors from the terminal, Audio would just say the sound card was just in use but that could be just with different linux distributions.

"comctl32"="native"
"gdiplus"="native"
"ie4"="native"
"iemigrat"="native"
"iernonce"="native"
"iesetup"="native"
"itircl"="native,builtin"
"itss"="native,builtin"
"jscript"="native"
"mlang"="native,builtin"
"mshtml"="native,builtin"
"msimtf"="native,builtin"
"msxml3"="native,builtin"
"odbc32"="native,builtin"
"odbccp32"="native,builtin"
"oleaut32"="native,builtin"
"riched20"="native"
"riched32"="native"
"shdoclc"="native,builtin"
"shdocvw"="native,builtin"
"shlwapi"="native,builtin"
"urlmon"="native,builtin"

This is working as of wine 1.1.9 just to clarify any questions about that.

Tips

The installer works fine with recent 1.1.1x wine.

The app won't log in unless you do alt-m and choose "Firewall - no proxies".

The app will crash after login unless you do "winetricks comctl32".

The app will crash when the instant message window comes up in wine 1.1.12, but not in wine-1.1.11.

When you send files and chat messages, they arrive ok at the other end.