Hi! PNGSquash has been rewritten from the ground up in version 2.0, and is available exclusively to the App Store. Get it here:
PNGSquash combines the top PNG compressors (that is, PNGCrush, OptiPNG, AdvPNG, and PNGOut*) into a streamlined interface for quick and effective compression. PNGSquash uses lossless compression (i.e., there is no change in quality), so it is ideal for web developers looking to save bandwidth.
*PNGOut cannot currently be bundled due to licensing restrictions, but there is a preference to enable it if you have it installed.