<a href="http://syn-k.sakura.ne.jp/dgen_psp/" target="_blank" >Syn-Z</a> who now has a shiny new homepage has released a new version of his Genesis (megadrive) emulator for the PSP, heres whats new via the translation:
Setting and retention
* Screen mode addition (Fit&Full)
* Sound volume setting and addition
* Sound left and right the bug which is opposite correction
Download from here --> http://psp-news.dcemu.co.uk/dgenpsp.shtml