Yes IH2 and Zen Lightbox work together for me also on Zen Cart 1.37.

I do have an issue with Firefox on one PC not finishing loading the large product image with "Lightbox" (I just observe a white rectangle with black background...no product image). But same issue does not occur in Firefox on another PC so I suppose this is a local Firefox config issue, related to finishing processing scripts. Probably something I need to adjust via Firefox about:config. Any ideas?

Regarding IH2 itself I do have issues with the zoom and hover not working on ZC 1.37. (but watermarks do work fine). I had all these IH2 features working on previous Zen Cart versions. Possibly a configuration issue on my part or PHP version issue. I note since move from server with PHP4 to server with PHP5 some issues with various mods have presented themselves. Appear to be related to GD. Better if I follow-up more on this in the IH2 thread. http://www.zen-cart.com/forum/showthread.php?t=35913