Unknown yellow popup near the dock

I'm still very new to Macs so hopefully this question isn't too silly...

I happened to notice a small yellow popup window that popped up in the lower right corner of my screen. My dock doesn't reach all across the screen, but if it did the popup would have been right at the top of it. I was across the room and couldn't read it before it disappeared but I saw it had two lines of text on it.

I've never seen that before and I haven't installed any new software.

Any ideas what it could have been? Can I check somewhere to see a log of it somewhere?

Sounds to me like this is a sticky note or something.

Does it look like the screenshot below?

MacHeadCase said:

Sounds to me like this is a sticky note or something.

Does it look like the screenshot below?

Click to expand...

I don't think so. I've never opened the Stickies program before and I don't think my popup had the darker yellow band on top.

What applications did you recently install? Any Instant Messaging program? Growl?

I installed MainMenu recently but it wasn't running. I had iChat running. I have growl installed but it wasn't a growl bubble.

Do you have Firefox? It could be the "Download complete" message.

Yeah, thought of that so I did a test download. It's not the same popup. I'm wondering if it could be a completed podcast auto download.