Well, I was reading a thread about the audio lag on the AVS Forums, and apparently it isn't all that uncommon. Here's the thread, the particular post I'm referring to is post #7.
http://www.avsforum.com/avs-vb/showthread.php?t=751752&page=1&pp=30
Anyway, it seems that utilizing the Game Mode feature on my TV helps a bit, but I'll be sure to try mike c's suggestion tomorrow after work.
mike c also answered my next question, about whether or not I can use the receiver's component inputs to plug in my video game systems - one of the reasons why I purchased this receiver is to take advantage of this, because my TV only has 2 component inputs, and I'm using 4 different systems with component. Is there a female to female cable for component that I can purchase at a shop like Radioshack?
Again, I appreciate all the help you guys have been giving. You all have been very patient, and I truly appreciate it.