Install gizmo in Nuke and create icon on menu

1: after you create your part of nuke script into a group (Edit>Node>Group>Collapse To Group (Ctrl+G)
2: Right Click on your Group node's properites> Manage User Knobs... to setup your own gizmo interface what ever you need
3: and click group node's Export as gizmo to your nuke's plugins folder ex: X:/Program Files/Nuke6.0v2/plugins/
4: click X and pick TCL to type the gizmo name you just save, to test saved gizmo working or not?
5: Create a text file call menu.py

toolbar = nuke.toolbar("Nodes")
# The "3DTools" menu
m = toolbar.addMenu("3DTools", "ReConverge.png")
m.addCommand("DepthGrade", "nuke.createNode(\"DepthGrade\")")

and save menu.py into your system folder below:
•Linux:
/users/login name/.nuke
/usr/local/Nuke6.0v2/plugins
•Mac OS X:
/Users/login name/.nuke
/Applications/Nuke6.0v2/Nuke6.0v2.app/Contents/MacOS/plugins
•Windows:
In the .nuke directory, which can be found under the directory pointed to by the HOME environment variable. If this variable is not set (which is common), the .nuke directory
will be under the folder specified by the USERPROFILE
environment variable - which is generally of the form drive letter:\Documents and Settings\login name\ (Windows
XP) or drive letter:\Users\login name\ (Windows Vista).
ex: X:\Documents and Settings\username\.nuke

depthGrade_example....

Show gixmo internal structure after export as gizmo
Gizmos are designed to be hard coded once you export them. To get around this and get back into the structure you will have to locate the .gizmo file in your plugin folder or wherever its stored. Now open this file in a text editor, and change the name "gizmo" on the third line from the top to "group" Now you can copy and paste the acsii text back into Nuke. Now you will have the gizmo back as a group node that you can Show contents and edit.

update: in nuke6 has "copy to group" on gizmo to quick reveal in qroup. cool!