iziBasic is indeed a great tool! Cheers aldweb!
You can have as many forms as you wish! I'm building iziForms, a tool to create forms by placing controls, etc. and I am myself experimenting with the various ways of "multiforming"... I'll post news if I get to any conclusion! Meanwhile you can try this methods:

1) You can create all the controls for your forms (every one with it's own ID, of course) and use subroutines to show/hide controls with the SHOW/HIDE instructions:

BEGIN
GOSUB CreateControls
REPEAT
A=WAITEVENT
' here one could use a variable
' to keep track of what form is
' active... Perhaps this will
' avoid some errors
GOSUB Form1Events
GOSUB Form2Events
UNTIL A=-1
END

CreateControls:
' controls for form 1
BUTTON #1,"GoToFormTwo",100,100,50,12
HIDE #1
' controls for form 2
BUTTON #2,"GoToFormOne",10,10,50,12
HIDE #2
RETURN

ShowForm1:
' now you could use smarter FOR...NEXT ' loops and use just one subroutine...
SHOW #1
RETURN

HideForm1:
HIDE #1
RETURN

Form1Events:
IF A=1 THEN
GOSUB HideForm1
GOSUB ShowForm2
ENDIF
RETURN

ShowForm2:
SHOW #2
RETURN

HideForm2:
HIDE #2
RETURN

Form2Events:
IF A=2 THEN
GOSUB HideForm2
GOSUB ShowForm1
ENDIF
RETURN


2) Other method is to use the DESTROY instruction like this:

Form1Start:
BUTTON #1,......
RETURN

Form1End:
DESTROY #1
RETURN

This way you can re-use the same control IDs, but I've had some problems with this - my code was full of garbage anyway :)

3) With the DESTROY method you can either keep track of what form is active in a variable if you're re-using control IDs or you can have separate Event Loops for each form:

BEGIN
(...)
GOSUB Form1Start
END

Form1Start:
BUTTON #1,......
REPEAT
A=WAITEVENT
IF A=1 THEN
GOSUB Form1End
GOSUB Form2Start
ENDIF
UNTIL A=-1
' save preferences and end
GOSUB SavePreferences ' not shown here
END
RETURN

Form1End:
DESTROY #1
RETURN

Form2Start:
BUTTON #1,......
REPEAT
A=WAITEVENT
IF A=1 THEN
GOSUB Form2End
GOSUB Form1Start
ENDIF
UNTIL A=-1
' save preferences and end
' as the user may want to get
' out quickly
GOSUB SavePreferences
END
RETURN

This is written without testing, though! I'll post a "robust" multi-form framework as soon as I figure out what is the best way to do it, but I think this shows the idea!
Hope it helps!