Find a mirror to add to your /etc/apt/sources.list here
https://www.debian.org/mirror/list so you can grap the older libdb4.8 packages needed. They can be found in the oldstable package repositories
Pick one to add. I'm in Australia so for example i added , deb
http://ftp.au.debian.org/debian/
oldstable main <-- notice the oldstable : )
Now prep for the build
sudo apt-get update
sudo apt-get install build-essential libssl-dev libboost-all-dev libdb4.8-dev libdb4.8++dev libminiupnpc-dev
clone a repository
git clone https://github.com/bitcoin/bitcoin.git
https://git.gitorious.org/bitcoin/bitcoind.git
you can git checkout 0.8.6 or Luke-jr has a good one v0.8.6.eligius4 at gitorious
once you have the souce you can
cd bitcoin/src
make -f makefile.unix USE_UPNP=1
grab something to drink and when you come back you should have bitcoind compiled on Linux Crunchbang-Waldorf.
Crunchbang is based on Debian Wheezy so , I imagine this will work on that also. : D