Two notes on this for the record: The software is called Slony-I. There will likely be a follow-up project called Slony-II that can do multimaster replication. So it would be wise to call the Debian package slony1 or something similar that includes the number.
I believe the yet to be released 1.1 series of Slony-I will support building without a PostgreSQL source tree. (At least some people have been in contact with me for advice regarding this.) This will likely also require PostgreSQL 8.0. So it's probably best to wait a little until this package can be built cleanly.
