meaning - "Would" vs. "Will"

Both would and will can be used in reference to a proposed future event. When the speaker is the agent of the future event, as in this case, will can be used both conditionally, to indicate that the event may or may not happen, and unconditionally, to indicate that the event is definitely going to happen:

I will be working on another script later this month.

I will work on another script later this month, if I have the time.

By contrast, would is typically only used conditionally, and usually implies that the speaker does not think the event will take place, or is flatly asserting that it will not:

I would work on another script later this month, if I thought I could find the time.

I would buy the tickets right now, if I had the money.

(Would is also sometimes used without the conditional to indicate a desire or wish—"I would speak with you, milord"—but this usage is archaic.)

To illustrate the difference, here's one way you could beg off politely:

I would like to help you with your project, but I will be working on another script this month, and so I will not have the time.