Network traffic?

[asterroc]

Is there any way to monitor the total traffic on my wireless network, not just my own computer, w/o going to my upstairs neighbors and asking them what they're doing? My reason is that when I upload images to Flickr, it clogs the entire network, so I'd rather do this when I know they're not using the network. By default, during the M-F workday is safe, as usually no one but me is home then, but I'd like to know more directly.

ETA: I'm using a Mac

ETAA: I'm using Flickr Uploadr, and another option might be to limit its bandwidth. Does it use a different port from Firefox, and if so how can I figure that out and restrict it? I found that HTTP uses port 80, and have set it to high priority in the router. How can I find the port for a different application (Uploadr) so that I can set it to low priority? (Alternatively, I could just set this whole computer to low priority, but I'd rather not.)