Basketball Equipment

Basketballs
Below I've noted (by Grade Level) the basketball size requirements that we follow for our league and that most AAU & the PIAA governing bodies utilize for boys and girls.
1st & 2nd Grade:  27.5"  (Youth Size)
3rd - 6th Grade (Girls): 28.5"  (Intermediate Size)
3rd - 4th Grade (Boys): 28.5"
5th - 6th Grade Boys:  29.5"  (Regulation Size)
The girls will utilize the same size (28.5") through Jr. High, Sr High and College levels.
The boys will utilize the 29.5 through Jr High, Sr High and College levels.
Not all basketballs are made alike and there is a difference between indoor and outdoor basketballs.   Below are some links to different styles and brands for comparison:

INDOOR:
Wilson Evolution:  Probably the best indoor ball available in the 27.5, 28.5 and 29.5 sizes.  
Dicks Sporting Goods Wilson NBA
The Wilson Evolution is a good investment if your child will be playing years of indoor basketball.  Reminder that once our daughters start the 3rd Grade they will be using the same size ball for many years.

OUTDOOR
Spalding NBA Street/Varsity/FastBreak:  Top Rated outdoor basketball
Dicks Sporting Goods Spalding NBA

The outdoor basketballs are typically made of rubber to hold up to the asphalt and concrete surfaces that they are played on.   They typically have a different "bounce" indoors and outdoors based on the surface they are played on.