Here is a working URL:
Category: VOIP
Mitel Connect download
article #1358, updated 566 days ago
SIP phone (VOIP) on Android
article #315, updated 3741 days ago
“CSipSimple” works quite well. It has auto-setup wizards for an excellent and very large variety of services, including both free and non-free varieties, internationally. Its market page is here:
https://market.android.com/details?id=com.csipsimple&hl=en
As of this writing it works just fine with FastVOIP and IPKall.