i was just wondering

i just heard about the R4 and all it's glory, and I'm still trying to figure out what i need to make everything work. simple stuff like, do i need emulators to play Roms from a diff system? what do i need to convert my audio/video files to? and whats the diff between ROM and ISO?
i appreciate the help

Yes, you'll need emulators for the systems that can be run.Audio/Video, use Moonshell to play (built into R4 firmware), convert video to nds mpeg format .dpg, with SUPER converter, or BatchDPG, Audio can be left alone, as long as it's mp3 etc.
More information on Moonshell can be found at the Wikipedia page http://en.wikipedia.org/wiki/MoonShellROM is the data in an image, or a class of storage which has been extracted generally from a solid state media (cartridge). ISO is the same, an archive or disk image taken from an optical disc.

Also, the R4 is no longer glory, it was 2 years ago, but now it's old, outdated, and a lot of work to make things function properly. If you have money then get a CycloDS, if you'd rather save $20 then get an Acekard instead, you'll be much happier with either of those.