For the PSX use Epsxe -totally free-, save states = save anywhere, load anywhere, or Bleem (search for bleeem, yes, with 3 Es in the web if you have an Athlon, or search for lockless bleem if you have an Intel and forget about that crappy CDkey), for up to 1024x768 or better resolution, 32 bits, antialiased, full screen beauty (depends on your 3d card).
These emulators sort of complement each other on the compatibility thing (around 70 % of the games running).
For fantastic cheating with both of the above, use PEC.
For slowing down your PC if the emulators go too fast, use Slowdown.exe, or just go for maxed out visuals, 32 bits, etc. Remember to cap your frames per second (I use 85 fps, cause when I use 200 fps the emulators sometimes acted weirdly)
As to emulating the PS2, it will probably arrive some day, but down hold your breath.
There is Dreamcast emulating in diapers, only one 2d compilation commercial game, sort of, ([url]
http://www.emulatronia.com,[/url] dreamer), looong way to go yet.
See ya
