If your company is in the process of upgrading to Notes 6, you know that there are certain personnel who can benefit from being able to access both the new and previous versions of Notes. This is particularly true with developers, who want to use Notes 6 immediately, but cannot use Domino Designer 6 to modify applications until all users of the application have been upgraded. Here is a tip that will allow you to run Notes 6 as your primary client and simultaneously pull up the R5 Domino Designer for development.
First, you have to have both Notes 6 and R5 installed on your machine. There are several ways to do this, but I simply make a copy of everything in my current notes directory in a new directory (e.g., notes_50), then upgrade to the new version in the original notes directory. The result is that I can launch either R5 or Notes 6 depending on which executable I call.
Note that you should have your NOTES.INI file in your original notes program directory before you make the copy to the new directory. Then, you can simply replace any references to the old path (e.g., c:notes) with the new path (e.g., c:notes_50).
Then, after you have upgraded your original instance to Notes 6, all you need to do is create a shortcut to NLNOTES.EXE in your R5 directory and follow it with the /DESIGN switch (e.g., c:notes_50nlnotes /design).
Now you can use Notes 6 for most of your activities, but you can always open the R5 Designer without having to close Notes 6 first.