PR of 4 is very good, especially for a new site!
Google's directory is actually from DMOZ. You have to get listed there -
www.dmoz.org
Getting into DMOZ is difficult. Read up about it first. Make sure you find the right location in the directory and submit only once. If you submit again, they put you back at the bottom of the pile again. They can take many months to include you. (The last response I got from them said I was in the queue, and to check back again in 6 months).