installing deb files from unstable or testing

[Israel Garcia <igalvarez@gmail.com>]

Some times ago (I could not find on google), I could create a deb file
for my lenny from unstable or testing debian (done remember now). I
remember I follow some steps from a blog or something and I
successfully created a new version of a deb file. Can you help me to
get this steps?

-- 
Regards;
Israel Garcia