Heavey Network usage ????????????

[Creature]

is there any program or somthing i can monitor who is connected to me,
or what my bandwith is doing and the ip of who it is on my line.

just lateley ill step away from my pc and then somthing starts usesen my bandwith, or somthing is connected to me..
the two little monitors next to the time on my desktop are
flashing or are constantly lite up to say somthing is happening on my internet

but yet i have IE closed Outlook is closed
and nothing that needs internet closed

ive done a spywear check and im clean

also when im playing games i get major lag spikes where its starts to use my bandwith again

ive closed all programs and checked but i think its somthing
outside of my pc

can anyone refer me to a decent monitoring program
or the best way to check it

[Jiff Lemon]

Obvious questions but:

Is your net connection shared? If so what machines you got on your network?
Are you running any sort of wireless access point?

[Moby-Dick]

if you wantto see whats going on with your PC, install a firewall such as outpost (http://www.agnitum.com/products/outpost/) or if you want want to monitor , have a look at Active ports ( http://www.protect-me.com/freeware.html )

[Creature]

no wireless and no ics

thnx for the links Moby