Transcribing from an MP3

Having agreed to transcribe interviews for a friend, I'm puzzled about how to get the functionality I get from a tape recorder using the MP3s she is about to send me.

Question: Would an MP3 back up 10 seconds or so in the recording (MP3) more easily and quickly using RealPlayer or some kind of computer software or an MP3 player? Turnaround time is critical.

I would rather not buy new equipment. Maybe I can just download the MP3s to my computer and use Real Player or whatever and move the little button back to replay and it would be about the same as the old mechanical way. But, if better using an MP3 player, is there a model of player or a function that would be the most useful for this kind of use?

[When I transcribe using cassette tape, I type along and when I don't hear a word or if I get behind, I just stop the machine, hit rewind or sometimes "cue review" and back up a little.]

In sum, I want to be prepared and am not sure about how to do review small segments of a recording the speediest and easiest with new technology.

Thanks for any input or ideas here!

Sal