If you try to install hellanzb via MacPorts, the method is currently broken on 10.6.. That's because py25-twisted fails to build on my 64bit system ( Ticket #20820).
The solution is to build using Python 2.5 instead of the default Python 2.6 in Snow Leopard. This avoids conflicts with Apple's own wiki and blog software, and problems with deprecated sys calls with HellaNZB.
#!/bin/bash
export PATH=/usr/local/bin/;
/usr/local/bin/hellanzb.py -D<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.hellanzb.daemon</string>
<key>ProgramArguments</key>
<array>
<string>/usr/local/bin/hellanzbd.sh</string>
</array>
<key>RunAtLoad</key>
<true/>
<key>StandardErrorPath</key>
<string>/Library/Logs/HellaNZB/error.log</string>
<key>StandardOutPath</key>
<string>/Library/Logs/HellaNZB/hella.log</string>
<key>UserName</key>
<string>*myusername*</string>
<key>GroupName</key>
<string>admin</string>
</dict>
</plist>Mac OS X Hints
http://hints.macworld.com/article.php?story=20090830200012294