I have never heard of an alternative IDE for Vb6. However, these two (free) VB6 add-ins are indispensable and will make your life easier – especially if there is a lot of code. They are equally effective for VBA in Microsoft Office.
MZ-Tools: provides a superb collection of IDE tools – finding unused variables, unused methods, a great “search all”, code snippets. Written by Carlos J. Quintero, to whom I now owe hours and hours of time.
http://www.mztools.com/v3/mztools3.aspx
And SmartIndenter, which takes care of all the auto-indenting. It does one thing and it does it well.
http://www.oaltd.co.uk/Indenter/Default.htm
