Weltall has informed us that he's back with another revision of CWCHEAT called CWCHEAT 0.1.6 Rev. E for 3.02OE/POPS. The name's still long, but that doesn't matter because in this version, you can finally load the memory cards from your PSX and PS2 emulators onto your PSPs.
According to weltall, these mem cards are stored and loaded in the ePSXe format. This means that you can load them directly using the best emulators out now (ePSXe, pSX) or convert them using any decent mem card management tool.
You can also use tools such as DexDrive to extract your saved games from your PSX memory cards or extract the single saves and put them in the ps2 with applications like ulanchelf. To do the latter, weltall says that you need to use psxmemtool to "extract the mc as ps1 remove the 0x80 header so it starts with SC and put the name you see in the header as the file name."
CWCHEAT can store up to 256 memory cards per game. They are identified using GAMEID-MEMCARDNUM.mcr. Here's an example from weltall: "for the first memory card of Xenogears which has id SLUS_00664 it will be SLUS_00664-0.mcr." These memory cards will be stored in /seplugins/cwcheat/mc and can be easily loaded to slot 1 or 2 by selecting the corresponding option.
Here's the changelog for CWCHEAT 0.1.6 Rev. E for 3.02OE/POPS:
fixed a little thing which for some game could make cwcheat not loading the id correctly
fixed the directory were the db is saved from the cwcheat interface now it's saved in the correct folder
new folder "mc" under /seplugins/cwcheat/
fixed some reported things here and there
BUILTIN SUPPORT to loading/saving epsxe (mcr) memory card to/from the psp emulator!!!
in this way you can load your own game saves from pc or psx/ps2 on the psp and vice versa!
but also go over problematic points in games.