Sorry I'm totally new to the After Effects and I would just like to know how to make titles for the opening credits of a short film I'm working on move slightly from right to left or vise versa.

Set the first position of your title whereever you want it to start from.

Twirl down the properties on the layer so you can see the position property and click the stop watch icon next to it to set a keyframe. Scrub forward on the timeline to when you want the title move to end and then move the title to the end position. It should automatically create a second keyframe and the title should now move from one point to the other as you scrub.

Done. Works the same for opacity or effect parameters. If you plan on using AE a lot, I highly reccomend you get this book to cover the basics.

http://www.amazon.com/Creating-Motion-Graphics-After-Effects/dp/1578202493/ref=pd_bbs_sr_1/103-1041975-1526254?ie=UTF8&s=books&qid=1179356538&sr=8-1

Thanks so much, I bought the book today as well.