Aside from trying to actually POST a conservative political statement on the Yahoo political board, you might try an indirect approach.
You might visit the financial site, finance.yahoo.com, to find stock message boards where political discussions are already taking place. (Should be very easy; they're everywhere.)
Call me slow...
I just wanted to chime in on the same topic (Yahoo Bias). I guess I just always expect a liberal bias in news, so my mind doesn't throw up any red flags when I see a pro-Kerry spin in most news--But yahoo's headlines recently have caught even my eye! Bush Bad, Kerry Good, Bush Bad, Kerry Good--I guess they think if they say it loud and long enough everyone will take it as truth.
I started looking for information on this online, and found out Yahoo news headlines are hand-selected, and Google headlines are selected by a computer algorithim--and get this: GOOGLE is the one accused of being biased!?
http://ojr.org/ojr/technology/1095977436.php
I joined freerepublic looking for a voice of reason! thanks!