Folks on the VB6 newsgroup report they have managed to get it working on Windows 7.
There’s this step-by-step guide on how to install the IDE on Windows 7 (including 64 bit).
If that doesn’t work (scrapes barrel) try this old tip about persuading the install not to install the Java VM? Link is now broken so here is the tip:
Before trying to install VB6. Create a new file, name it msjava.dll and place it in your windows directory. The file can be zero length. You can then happily install without the prompt to install an old version of Microsoft’s flavour of Java. Once you have installed VB6, delete the msjava.dll otherwise windows update will prompt you to update it.
Or (scrapes hole in barrel) these tips from an article about getting the IDE working on Vista?
Footnote: if developing with ADO, be aware of this.