I know that Media Player files are available on the Internet, with audio/video clips. Is it possible to make your own, like you can make your own word documents, and if so, how? Can video cameras or tapes be used as sources?
Wow, that’s an extraordinarily broad question. Perhaps you would like to narrow it down a bit? E.g., would you like to make a music file or a video file? What source is it going to be coming from?
I want to make music files and video files. Can this be done using Real Player? I have material on analogue video/audio tape and which I want to use. I have a DVD-ROM if that helps.
Ah, that’s better. Audio tape is fairly easy to read from–all you have to do is run a line from the player to your sound cards’ line-in port and record with a program. The program will most likely save it as a .wav file of some sort and you’ll need to convert it to a more compact format, such as realplayer or mp3. Since I don’t record directly from my line-in port very frequently, I can’t really make any recommendations, but if you go to download.com, I’m sure you’ll find a directory with a heck of a lot of usable suggestions.
The better your sound card and the better the source tape player, then the better results will be.
Now, getting video into your computer is a heck of a lot trickier. You’ll need a special bit of hardware, such as a tv tuner card (for relatively low quality video) or a firewire card.
If you spend less than $100, you’ll probably wind up with a tv-tuner card and the ability to make relatively blurry video files. Hauppage and ATI both make decent products.
More than that, and you get into the professional realm. I don’t know much about that range…hopefully someone else will chime in.
To make realplayer files, you’ll need Realproducer, which is a snap to use. It’s available somewhere on Real.com. Just install the program, go through the wizards and your source file is converted. Very easy. It’s not a very good format, but it is painless to create.
Blurry? Eh, I don’t know about that. I get some pretty decent results from my cheap TV card. Only difference is that the colors look a little washed out compared to the real TV. The trick to getting decent results is to never use the TV card’s built-in tuner. Most TV cards have an RCA-in or an S-video-in. Run a cable from your VCR to the card and use the VCR as the tuner. Not only will you get much better results, but you’ll be able to capture a playing VHS tape, a video game, or anything else you have hooked up to your VCR (excepting a DVD player).
Slortar, note that the OP asked about WMP files, not RealPlayer (and I don’t blame him). RP is a good codec for cartoons, but that’s about it. It’s also a dead-end format, in that it’s a difficult and error-prone process converting a RM file to an MPEG.
Windows Media Encoder is the product you’re looking for.
You mean WMA (Windows media) format files? I suppose you can.
Oh, I’d say him asking if it can “be done using Real Player” counts as asking about Realplayer format. Almost by definition, in fact. 
Hm. Just my experience. I have a sub $100 tv capture card (ATI) and the results aren’t really that fantastic. I guess your mileage will vary depending on what brand of card you get. Of course, I haven’t tried it with my new VCR (the old one was awful), so maybe my opinion will improve next time I have a go at it.