A Solution for sniffing

[fadi () lebrocks com]

Hello Folks,
I think i am being sniffed by somone on my network, and i was wondering. is 
there an application to check wether i am being sniffed or not, and if i 
was, how can i fix that ?(like PGP for mail, what about other protocols) 

P.S. : Running Linux Slackware 8.1 (if that would help) 

cheers,
Fadi R. Khouja