Hi Karen,
My Yahoo usually updates pretty fast, but you have to ping every time you add a new entry. Did you send a ping or is your software set up to automatically ping Yahoo and the other services?
I have WordPress and you can set it up to auto ping, but I don't because sometimes after I publish a new entry and look at it I may decide to shorten or change the title or something.
So I manually ping all the services once I'm sure it's right. I use
www.pingomatic.com which has been down a lot lately. Once you enter your info the 1st time, then just bookmark the page and you never have to enter again. So it only takes a second to send a ping after each new entry. When it's down I use
http://www.pings.ws/ which basically does the same thing.
Hope this helps and best of luck!