The Book of PF, 2nd edition, update 01

In OpenBSD 4.9, wpa-psk(8) was replaced by wpakey option to ifconfig(8) 

Pages 47 and 52:

In OpenBSD 4.9, the WPA key functionality previously handled by the
wpa-psk(8) utility was merged into ifconfig(8), and the configuration
syntax was simplified accordingly. The hostname.if line for a WPA
access point configuration in the OpenBSD 4.9 style on page 47
becomes:

up media autoselect mediaopt hostap mode 11g chan 1 nwid unwiredbsd \
 wpakey 0x1deadbeef9

The examples involving wpa-psk(8) on page 47 are no longer needed on
OpenBSD 4.9 and newer, and the wpa-psk program was removed from the
OpenBSD base system before the 4.9 release. 

The hostname.if line for an OpenBSD 4.9 WPA client on page 52 becomes:

up media autoselect mode 11g chan 1 nwid unwiredbsd wpakey 0x1deadbeef9

followed by dhcp (for ipv4 networks) or rtsol (for ipv6 networks), or
both for dual-stack configurations.