I was just wondering if arduino (Make: Ultimate Arduino microcontroller Kit) can control a fan of this size: http://www.amazon.com/Lasko-3733-20-Fan-Box/dp/B00002ND67. Looking at preexisting projects, I mostly see arduinos modified for computer fans, but I have wondered if I need additional shields for larger fans. Does anyone know of online projects for some pointers? Also, for sensing temperature, which temperature sensor should I buy?
An Arduino can control a fan like that just fine, but not directly. A relay or some similar circuit is needed. The Powerswitch tail is an easy and safe way to go.
As for temperature sensors, there are many common and popular parts. TMP36 is an analog sensor, DS18B20 is digital, just as two examples.
Welcome to the forum!
PS: Many sensors and related information here:
http://playground.arduino.cc/Main/InterfacingWithHardware#envtture
For a project that simple, the Arduino is certainly overkill. Unless your primary interest is the fun of putting everything together, you can buy the equivalent self contained unit for about the same total price (and it would be more reliable), for example http://www.amazon.com/Cool-Attic-CX1500-Power-Ventilator/dp/B000LNII4Q