From VoIP.ms Wiki
Configuration Details for the Taki Softphone on a Blackberry
Step 1: Start the Taki App
Step 2: Once the Taki App has started, "Accounts" tab will be open to start the configuration.
Step 3: Fill in the information according to your account.
Your Name: John Smith (Your CallerID Name or Description)
Username: 100000 (This is your SIP/IAX Main Username showing up in your customer portal)
Password: *********** (This is your SIP password, you can verify it from the customer portal)
Domain: atlanta.voip.ms (Please use one of the multiple VoIP.ms servers)
Step 4: Click on "Save" button.
Step 5: Your softphone should be ready to make calls.
Click on "Dial" tab. Type your destination phone number and press "Call".
Use "Contacts" tab to call contacts from your address book.