http://www.michaelkingston.fi/retroband/
RetroBand used to be commercial but now it's freeware since today.
It's somewhat outdated but still works well with all the latest Windows releases and modern hosts. It also works in 64-bit hosts using jBridge. It may also work with some hosts internal 64-bit wrappers, but I personally prefer jBridge for all things wrapping.
For OSX you're out of luck, unfortunately. You can try with 10.9 Mavericks and misc. plugin wrapper related sorcery but it's probably not going to work and there will not be updates ever so don't ask.
RetroBandLite was always freeware. Due to the simplified interface it's actually the one I personally always try first. It's much easier to understand, faster to tune and get results. Don't be fooled by the fact it doesn't do oversampling like its big brother. It still sounds awesome.
If these still work on your particular host or platform, have fun!
Regards,
Kingston
