mongodb-stable package installed from 10gen repo. I can
start the service fine with 'service mongodb start', but neither
'service mongodb status' nor 'service mongodb restart' seem to work:

root@db01:/var/log$ service mongodb status
mongodb stop/waiting
root@db01:/var/log$ service mongodb restart
restart: Unknown instance:
root@db01:/var/log$ ps ax G mongodb

17605 ? Sl 0:00 /usr/bin/mongod --config /etc/mongodb.conf

The config is pretty bare:
dbpath = /data/mongo/db
logpath = /data/mongo/logs/mongodb.log
logappend = true
fork = true
directoryperdb = true
rest = true

The discussion linked to below indicates that this is because of "fork = true" setting.

http://groups.google.com/group/mongodb-user/browse_thread/thread/0c074b6a11eac29b