infrared serial communication

hello

i would like to let two arduinos communicate via infrared. they should check if they see each other and transmit some information.

is it possible to create a simple infrarred serial (digital port 1/2) communication?

another way is to create a connection via ir emitters and receivers (http://www.produktinfo.conrad.com/datenblaetter/150000-174999/171069-da-01-en-IR-Empfaenger-Modul_TSOP_1736.pdf).
therefore i have to create a 36khz pwm pulse for the emitter led. how do i get exactly that frequency via analogWrite()?

thanks

michael