Three

The Ahobila perumal, Narasimhar is well sung and praised by

1. Aadhi Shankarar, 
2. Udayavar Ramanujar and
3. Sri Madhava Chariyar. 

These 3 great persons are considered to important and should be given respect, since they worked very hard to attain the perumal and they worked hard for the humanity to live their life in peace.

Other than these 3 great personalities, 3 more who were given the Sthanam (position) (position) of Alwars (ie)

1. Garudalwar, 
2. Pragaladhalwar and 
3. Thirumangai Alwar 

have also praised on this Ahobila varadhan.

Theerthams of Ahobilam

http://www.divyadesam.com/hindu/temples/andhra/ahobilam-theerthams.shtml or
http://andhradivyadesams.blogspot.in/2009/01/thiru-singavel-kundram-ahobilam.html or
http://www.srivaishnava.in/component/k2/item/74-74ahobilam-singavel-kundram.html 

Navaratri

Nrisimha Navaratri is celebrated for nine days; begins on Vaishakha Shukla Panchami and ends on Narasimha Chaturdashi or Narasimha Jayanti day (Vaishakha Shukla Chaturdasi). This festival is celebrated with gaiety and fervor

1. Special pujas, 
2. Abhisheka, 
3. Archana, and 
4. Aarti 

are performed to the deity in Mysore Datta Peetham.

Highway Only Way

http://highwayonlyway.com/2012/01/26/ahobilam-day-1-where-mythology-comes-alive/

Hare Krishna / Blog

http://www.harekrsna.com/philosophy/caitanya/kshetras.htm
http://www.harekrishnablog.com/your-corner/70-galleries/508-ahobilam-the-land-of-narasimha 

Strikes

http://www.youtube.com/user/ashokstrikes/videos?flow=grid&view=0

Sai

http://www.starsai.com/ahobilam-sri-nava-narasimha/