Hi Chiru Varma,
If you want to activate service execute SICF transaction and provide your service name.
click on execute.
then it will display the hierarchic structure.
select your service right click active service.
then the service will active.
go through this link u may get better idea..
http://www.sapdev.co.uk/webapps/sicfhome.htm
Thanks & Regards,
Srinivask