Hi,
since I didn't find much on the topic here, I thought I'd share my experiences with ISPcp on Lenny.
Some things I noticed so far:
chkrootkit is not included in Debian testing because of an unfixed
bug they have in their most recent version.
libapache2-mod-cband has been removed by the debian admins because their is no active maintaince for it.
libsasl2 has no installation canidate, but can be replaced by libsasl2-2. (perhaps a change to the package list, would be nice)
proftpd-mysql is no longer present under testing. Maybe mysql support was included directly into the proftpd package (will lett you know, once i get to it)
PHP4 is not in the package list, which is good, since Debian is
dropping support for php4 beginning with lenny. I guess the fastcgi config will need some manual tuning to use the php5 binaries by default.
Beside of the above mentioned the lenny package list seems to work, will get back here as soon as something else hits my way.
Btw.: According to an
article on pro-linux there will be a feature freeze upon debian testing in march. So some of things listed here, may stay like this in the stable release of lenny and should be considered upon further development.