Add the following line to /etc/apt/sources.list to get updates from this site,
for sid/lenny:

deb http://etc.inittab.org/~agi/debian/libapache-mod-security ./

Etch users can get the packages with this line in /etc/apt/sources.list:

deb http://etc.inittab.org/~agi/debian/libapache-mod-security/etch ./

Sarge users can get the packages with this line in /etc/apt/sources.list:

deb http://etc.inittab.org/~agi/debian/libapache-mod-security/sarge ./

AMD64 users may find packages at:

http://kos.li/files/debian/  (Thanks to Martin Kos)

Alberto.