I understand that ちょっと待って means "please wait a while".
But I did hear some people using ちょっと待った for the same meaning (maybe).
So what is the difference between these two and when should we use 待って or 待った？
Needless to say, both have the same meaning and both are informal.
ちょっと待って is more versatile in that basically anyone, regardless of age, gender and other general characteristics of the speaker, can use it in nearly all informal situations where one wants to ask another person to wait a second.
ちょっと待った fairly strictly chooses the speakers and situations. Male speakers use it much more often than female speakers. The phrase sounds a little more curt / urgent / dramatic, etc. to our native ears, which is probably why it is used in fiction often. If I may say this, I DO NOT recommend that a Japanese-learner use this phrase actively unless he is nearly fluent and capable of keeping the other parts of his speech at the same informal and/or lively level.
In comparison, the phrase ちょっと待て, mentioned above in the comments by @Snailboat, sounds more like a serious order than a request. With the small っ, it sounds more like a request.