how effective is function point analysis ?

in s/w cost estimation , especially oo projects , how effective is function point analysis ? anybody is using anyother method ?
any software for cost estimation ?

Function point analysis is not always appropriate - I found http://www.softwaremetrics.com to be very informative.
Alternative to FPA - You can consider Use Case Points, which emphasises use case to test case mapping. however this is still an evolving technique. The following paper by SureshN may be of interest to you:
http://www.cognizant.com/cogcommunity/presentations/Test%20Effort%20Estimation%20Using%20Use%20Case%20Points.pdf
I had problem viewing the pdf file, alternatively use the http conversion:
http://www.google.com/search?q=cache:CR06xQLgz_kC:www.cognizant.com/cogcommunity/presentations/Test%2520Effort%2520Estimation%2520Using%2520Use%2520Case%2520Points.pdf+total+effort +estimation+using+use+case+point&hl=en
Subbu.

thanks for the link , subbu. you can right click on the link & save it on the disk & view. in , html version , all the important diagrams are missing.
are there any case tools for software cost estimation used in the industry ? i have heard about rational . anything else?

People claim that COCOMO is superior to FP. You may want to take a look at that also.
Personally, I am not familiar with Software Engineering.