removing duplicate rules

[amit pasari <amit@xxxxxxxxxxxxxx>]

hello,
i have been using iptables for quite sometime , Now my problem is , if by 
make i add multiple type of same rule in iptables it accepts N number of 
entries . So can any body tell me how to aviod that or can i check the same 
rule exists before Appending it into the table.
Eg : iptables -A INPUT -d 192.168.0.2/32 -i eth1 -j DROP
i have add the above rules 10 times 20 times but the system never says the 
above rule exist . Can anybody tell me how can i check or aviod .

thanks in advance .

amit