I have found it easiest to use a program called Camtasia Studio You can use it to record your playing as a movie (though you need an emulator video plugin where you can adjust the frame rate to about 5 or so). I suggest 5 because Camtasia has a problem for me when I tried to record over 7 FPS, it tends to drop a lot of frames at the higher rates (which is why I chose to record higher than the playing rate), though it does suggest turning of 3d Hardware acceleration, but the video plugin I used required it so it wasn't an option for me. After you record your movie you can play it back "frame by frame" and take screenshots of the character(s)/poses you desire, then "extract" the character from the background.
Yeah it's a lot of work... boring too... but it gets the job done
Lord_Ball's method will surely work, but I personally don't see it as too efficient, and requires additional hardware I believe. If you've already got that video that you made on your computer, than it shouldn't be too hard. I know that in quicktime you can go frame by frame and copy the contents of the frame, then into a program such as paint.
If you have animation shop, or a similar program, open the movie (avi file) in it and export each frame as a bmp or gif.
Using PhotoShop it is easy to crop/resize each sprite to the desired size by use of Actions (PS macro functions - Thankyou Orange_Ribbon for teaching them to me ).
I did that with the DKC mod I started a month or so ago. Never finished it though I got DK about 30% complete and one level. That's all
i'd try ripping from something else just for practice. if your new to sprite ripping, ripping PSX/PS2 is a bitch and is hard to achieve nice results. an emulator may distort the original look of the sprites, experiment with different drivers/plugins and emulators. Fraps is a good program for recording also.
I ripped snes sprites from zsnes emulator and it was really easy because you can turn the background off. But with psx it's really hard because you can't turn the background off. I'll be able to do it but it's gonna take a while.
you can use a program called pcxclean.exe that will remove unwanted pixels from a .pcx file, and does batch jobs. All you do is rip a few sprites manually and make a pallete with just the colours your sprites use, make the transparent colour the first entry, #0
export the palette in photoshop as an .act file
the app will remove all colours not in the palette and replace them with the transparent colour.
a brilliant app tell me if you want me to send it to you