From the FAQs :
What if I don't get a good answer?
In order to get good answers, you have
to put some effort into the question.
Edit your question to provide status
and progress updates. Document your
own continued efforts to answer your
question. This will naturally bump
your question and get more people
interested in it.
If, after two days, you still don't
have an answer you like, you can offer
a bounty. Slice off a bit of your own
hard-earned reputation -- anywhere
from 50 to 500 -- and attach it to the
question as a bounty. We'll even throw
in 50 reputation to sweeten the deal.
The bountied question will appear with
a special icon in all question lists,
and it will also be visible on the
home page Featured tab.
Once initiated, the bounty period
lasts seven days. If you mark an
accepted answer, your bounty is
awarded to the answerer (do note that
accepted bounty answers are permanent
and cannot be changed). If you do not
accept an answer in seven days, the
top voted answer will automatically
become the accepted answer, and half
your bounty will be awarded to that
answer. You will always give up the
amount of reputation specified in the
bounty, so if you start a bounty, be
sure to follow up and accept the best
Of course, bounty awards, like all
accepted answers, are immune to the
daily reputation cap and community