I just went ahead and recorded mine on Sound Recorder (for Windows). It saved the files as .wma and I don't think that was a problem.
So if you have any sound recording program (even an extremely basic one) just go ahead and read the lines into the mic. If you're doing multiple lines you can record 'em in one session and save the file. I listened to mine a couple times to make sure I wasn't too loud, that I didn't breathe into the mic, and that there wasn't any crazy background noise, and once I liked how it sounded I went ahead and emailed it to ZaichikArky. I'd recommend leaving two or three seconds or so at the beginning and end of each recording so that it won't be hard to cut apart and implement into video.
Good luck, have fun with it, and don't worry; none of us are professionals.