Brandon Beachy is currently posting a 4.11 K/BB ratio after 23 GS and 131 IP. This is pretty impressive for a 24 year old, especially if he keeps it up for the rest of the season. To put this in a historical perspective I used data from the Baseball Databank to call up all SP seasons since 1920 with a K/BB greater than 4, a K/9 greater than 9, and minimum 100 IP [age 24 and younger].
Four pitchers came up: Oswalt in '01, Prior in '03, Liriano in '06, Peavy in '05. This is some encouraging company.
After removing the 9.0 K/9 qualification some really interesting names show up:
Seaver ('68), Clemens ('84), and Sutton ('66) are all Hall of Famers. Saberhagen ('85) is no slouch either.