Hak files are the preferred way to distribute and use custom content.
Use the tools listed below to create hak files for NWN2.
tani's ERFinder is a great tool for creating hak files.
ERFinder is a small tool like the old hak-packer of nwn1. it can open/import/export/save any ERF-formatted files for nwn2, especially HAK, MOD, PWC and ERF itself. it uses OEIShared.dll from your nwn2-installation for all file-io (so it should be placed in your nwn2-folder) and needs .net 2.0 (like all nwn2 tools). it complies to the new ERF v1.1 format, thus allowing filenames to be 32 charakters long (hak-packer from nwn1 only supports v1.0, limiting filenames to 16 chars).
Get it from the vault:
http://nwvault.ign.com/View.php?view=NWN2Tools.Detail&id=9
Another tool for creating hak files is Ranmanu's Encapsulated Resource File Editor.
Edits, imports or exports data from Encapsulated Resource File files also known as ERF files (.HAK, .MOD, .ERF and .NWM).
Can be used for NWN1 (ERF version 1.0) as well as NWN2 (ERF version 1.1).
Get it from the vault:
http://nwvault.ign.com/View.php?view=NWN2Tools.Detail&id=30