Sorry if I didn't specify, but complete suggestions as to render settings and output module would be very helpful. Thanks.
If you want us to give you step-by-step instructions, you need to meet us halfway and tell us much more.
What, exactly, do you wnat to do with this movie? Play it on your computer? Email it to someone else and play it on their computer? Upload it to YouTube so that someone can play it from there?
Also, the basics about your system are always useful: At the bare minimum, what are the version numbers of After Effects and your operating system?
In the meantime, read this page and the pages that it points to:
'to play in a media player' - just good quality playback through quicktime or vlc media players, not to be emailed or uploaded please.
I'm on AE CS4 on Windows Vista.
You asked for both render settings and output module settings.
First, the render settings, since that's the easy part: You probably don't need to change these from the defaults, since the default values are for the full-resolution, full-quality render.
Regarding the output module settings: You didn't say what your composition frame size is, so I'm going to assume 1920x1080. You don't want to use the default codec for QuickTime (Animation), since it makes files that are very large and tend to play back poorly. (They're great for intermediate files in a post-production workflow; just not for playback.) One good option within QuickTime is MPEG-4 Video. If you choose QuickTime from the Format menu in the Output Module Settings dialog box, you can then click Format Options and choose MPEG-4 from the Compression Type menu.
Another good choice for playback is F4V (Flash video). Just choose F4V (H.264) from the Format menu in the Output Module Settings dialog box and then click Format Options and choose F4V - Same As Source from the Preset menu.
The settings and quality for H.264 / MPEG-4 output are much easier/better in CS5 and CS5.5. These are very useful formats, since the quality is quite high for such a high compression rate, so we've been tweaking these to get them as good as possible. For this reason, instructions for CS4 for these formats look quite a bit different than instructions that you are likely to see for the later versions.