Ipcall

I currently have IP kall which gave me an inbound number were people call me and it works with any SIP. However if people call me in that number will it still contribute to our pot or do I need to use one our voipuser numbers.

No, it will not contribute as it is the termination of PSTN leg of the call produces the contribution. It does contribute to the IPKall "pot" as they terminate the PSTN leg and that is how they finance the IPKall service (as far as I know). Your call will arrive at Voipuser via internet voip and it cost us almost nothing to carry it but does not contribute anything to the pot (and we do not charge you for the call). To contribute to the pot you would have to call the PSTN voipuser PSTN numbers and that would be expensive from the US.

I tried to forward my IPKALL number to my username [!at] sip.voipuser.org (replace the [!at] with a @) but I just get a busy tone and nothing happens.

Is it possible to forward IPKALL to voipuser a/c?

goshainganj :

I tried to forward my IPKALL number to my username [!at] sip.voipuser.org (replace the [!at] with a @) but I just get a busy tone and nothing happens. Is it possible to forward IPKALL to voipuser a/c?

Yes, but remember Voipuser is having problems at present.
I had an IPKall account for a while and used to forward in to my free account at us.voxalot.com (also gives iNUMs with each account) were it worked OK. Something else you could try is SipSorcery as it may give you some of the options that you seem to be looking for.