Sean McNamara and Marten van de Sanden: humm ... strange problems. since Christmas, I connect to my Linksys WRT610N Dual Band router with WPA2/AES encryption. I have no problem of connection. I'm under Ubuntu 9.04 i386 with a 2.6.32 linux kernel.

The "iwconfig" command says with "2.4 GHz" band:
$ iwconfig ra0
ra0       Ralink STA  ESSID:"****_1"  Nickname:"RT3572STA"
          Mode:Managed  Frequency=2.462 GHz  Access Point: **:**:**:**:**:40   
          Bit Rate=130 Mb/s   
          RTS thr:off   Fragment thr:off
          Link Quality=100/100  Signal level:-45 dBm  Noise level:-63 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

The "iwconfig" command says with "5 GHz" band:
$ iwconfig ra0
ra0       Ralink STA  ESSID:"****_2"  Nickname:"RT3572STA"
          Mode:Managed  Frequency=5.18 GHz  Access Point: **:**:**:**:**:41   
          Bit Rate=270 Mb/s   
          RTS thr:off   Fragment thr:off
          Link Quality=100/100  Signal level:-65 dBm  Noise level:-56 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

The "iwpriv" commands say:
$ iwpriv ra0 show AuthMode
ra0       show:	WPA2PSK

$ iwpriv ra0 show EncrypType
ra0       show:	AES

$ iwpriv ra0 show NetworkType
ra0       show:	Infra

$ iwpriv ra0 get_site_survey
ra0       get_site_survey:
Ch  SSID                             BSSID               Security                       Siganl(%)   W-Mode  ExtCH    NT
36  ****_2                            **:**:**:**:**:41    WPA2PSK/AES            68              11a/n       ABOVE  In
11  ****_1                            **:**:**:**:**:40    WPA2PSK/AES            100            11b/g/n    NONE    In

Do you build the RT3572 driver (version 2.3.0.0 / 12/22/2009) with the following options in "os/linux/config.mk" ?
# Support ATE function
HAS_ATE=n

# Support QA ATE function
HAS_QA_SUPPORT=n

# Support XLINK mode
HAS_XLINK=n

# Support Wpa_Supplicant
HAS_WPA_SUPPLICANT=y

# Support Native WpaSupplicant for Network Maganger
HAS_NATIVE_WPA_SUPPLICANT_SUPPORT=y

#Support Net interface block while Tx-Sw queue full
HAS_BLOCK_NET_IF=n

#Support DFS function
HAS_DFS_SUPPORT=n

#Support Carrier-Sense function
HAS_CS_SUPPORT=n

# Support for Multiple Cards
HAS_MC_SUPPORT=n

#Support for IEEE802.11e DLS
HAS_QOS_DLS_SUPPORT=y

#Support for EXT_CHANNEL
HAS_EXT_BUILD_CHANNEL_LIST=n

#Support for Net-SNMP
HAS_SNMP_SUPPORT=n

#Support features of 802.11n Draft3
HAS_DOT11N_DRAFT3_SUPPORT=y

#Support features of Single SKU. 
HAS_SINGLE_SKU_SUPPORT=n

#Support features of 802.11n
HAS_DOT11_N_SUPPORT=y

HAS_KTHREAD_SUPPORT=y

#Support statistics count
HAS_STATS_COUNT=y

#Client support WDS function
HAS_CLIENT_WDS_SUPPORT=n

#Support for Bridge Fast Path & Bridge Fast Path function open to other module
HAS_BGFP_SUPPORT=n
HAS_BGFP_OPEN_SUPPORT=n

#Support MAC80211 LINUX-only function
HAS_CFG80211_SUPPORT=n

Notice : I cannot enable "HAS_CFG80211_SUPPORT" because the build failed.
CC [M]  [...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.o
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c:349: attention : initialization from incompatible pointer type
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c: In function ‘CFG80211_RegHint11D’:
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c:698: erreur: implicit declaration of function ‘regulatory_hint_11d’
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c: In function ‘CFG80211_RegRuleApply’:
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c:731: attention : unused variable ‘IdReg’
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c: In function ‘CFG80211_Scaning’:
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c:977: erreur: ‘struct ieee80211_channel’ has no member named ‘max_bandwidth’
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c:979: erreur: ‘struct ieee80211_channel’ has no member named ‘max_bandwidth’
[...]/2009_1222_RT3572_LinuxSTA_V2.3.0.0/os/linux/../../os/linux/cfg80211.c:983: erreur: ‘struct ieee80211_channel’ has no member named ‘max_bandwidth’

any idea ?