for transparent proxying, see my posts for more detail
   http://m0n0.ch/wall/list/?action=show_msg&actionargs[]=186&actionargs[]=63

and please note,
1) it's based on 1.2b9. i'll build a new image for 1.2r when i have
time, next month maybe.

2) the link for the image file should be
http://61.132.118.190/m0n0/1.2b9/generic-pc-1.2b9.0508262324.img

3) the inbound rule for transparent proxying is wrong. here is the correct one
>
>3. add inbound/outbound nat rules for transparent proxying
>        inbound rules 1:
>                Interface:                        LAN
>+              Source:                          not A.B.C.D5/32
>                External address:                Any Address
>                Protocol:                        TCP
>                External port range.from:        80
>                NAT IP:                        A.B.C.D5
>                Local port:                        3128