Yes. However, free calls to certain countries are only active for 90 days after the date of your last topup. (Buying a topup entitles you to 90 "freedays"). With some other Betamax brands (e.g. Rynga.com) it is 120 days. Also it is a maximum of 300 minutes per week of free calls, measured over the last 7 days and per unique IP address. In practice sometimes it is less. If you exceed this, there is a nominal per minute charge.
You can see all the SIP settings for your device at
FreeCall | sip with freecall
You can take incoming calls at
username@sip.freecall.com. You can also point incoming numbers (DID's) from other service providers to this address (such as the free USA Washington State based ones you can get from IPkall.com) .
You can also arrange to have all incoming calls (from your SIP address and DID) forwarded to your own mobile phone or landline telephone. If this is a USA based number, it is obviously done for free, provided you are within your 300 free minutes allowance. If you are abroad on a local SIM, you can get them sent there.
I think that's it in a nut shell. Just a bulk standard VoIP platform basically.