In addition to tip 060, "Add new options to that right click in Explorer", You can add an new option to every right click by editing the Registry at HKEY_CLASSES_ROOT\* and Adding Value EditFlags of type REG_BINARY. With the Hex button checked, enter 02000000.
In Explorer select view/options/File Types. Highlight the * entry and click the Edit button. Click the New button. In the "Action" box, type "open with xyz". In the "Application ..." box, browse to the program you wish to use. OK/Close out of the dialogue boxes.
Now, when you right click in explorer, you will always be able to "open with xyz".
To restrict this functionality to Unknown file types, perform the Registry edit on HKEY_CLASSES_ROOT\Unknown instead.
Note: This procedure will prevent you from using the Office 95 and 97 Tool Bar and I haven't figured out why, yet. You may prefer Tip 092.To undo this change:
Use regedt32.exe to navigate to HKEY_CLASSES_ROOT\*\Shell. In the right hand pane, delete the data value from the <No Name> entry. Then navigate to HKEY_CLASSES_ROOT\*\ShellEx and delete any Value Names.