I have updated to hal 0.5.11~rc2-1ubuntu2 this morning (installed 8.04 beta yesterday as an upgrade from 7.10), and even after a reboot am still seeing network manager 0.6.6-0ubuntu2 consume 100% CPU.  This occurs when I remove my ethernet cable and network manager attempts to connect to my wifi network.  The following is from the syslog:

Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) started... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 1 of 5 (Device Prepare) scheduled... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 1 of 5 (Device Prepare) started... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 2 of 5 (Device Configure) scheduled... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 1 of 5 (Device Prepare) complete. 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 2 of 5 (Device Configure) starting... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1/wireless): access point 'WhiteStar' is encrypted, but NO valid key exists.  New key needed. 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) New wireless user key requested for network 'WhiteStar'. 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 2 of 5 (Device Configure) complete. 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) New wireless user key for network 'WhiteStar' received. 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 1 of 5 (Device Prepare) scheduled... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 1 of 5 (Device Prepare) started... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 2 of 5 (Device Configure) scheduled... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 1 of 5 (Device Prepare) complete. 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1) Stage 2 of 5 (Device Configure) starting... 
Mar 22 10:48:18 swift NetworkManager: <info>  Activation (eth1/wireless): access point 'WhiteStar' is encrypted, and a key exists.  No new key needed. 
Mar 22 10:48:19 swift NetworkManager: <WARN>  nm_signal_handler(): Caught signal 11.  Generating backtrace... 
Mar 22 10:48:19 swift NetworkManager: ******************* START **********************************
Mar 22 10:48:19 swift NetworkManager: (no debugging symbols found)
Mar 22 10:48:19 swift NetworkManager: Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
Mar 22 10:48:19 swift NetworkManager: (no debugging symbols found)
Mar 22 10:48:19 swift last message repeated 10 times
Mar 22 10:48:19 swift NetworkManager: [Thread debugging using libthread_db enabled]
Mar 22 10:48:19 swift NetworkManager: [New Thread 0xb7b2f720 (LWP 4798)]
Mar 22 10:48:19 swift NetworkManager: [New Thread 0xb7b2eb90 (LWP 6519)]
Mar 22 10:48:19 swift NetworkManager: [New Thread 0xb732db90 (LWP 6500)]
Mar 22 10:48:19 swift NetworkManager: (no debugging symbols found)
Mar 22 10:48:19 swift last message repeated 9 times
Mar 22 10:48:19 swift NetworkManager: 0xb7f2f410 in __kernel_vsyscall ()
Mar 22 10:48:19 swift NetworkManager: ******************* END **********************************

If I kill NetworkManager (sudo kill -9), reconnect my ethernet cable and then restart NetworkManager, it does restore my wired connection.