Whenever I try to install Voice Search I get "install failed" error in the notification bar. Supposedly it has something to do with signatures but I know better than to ask Cyanogen about it. Any ideas?
I spotted this advice on the post on the Google Mobile Blog announcing the new Voice Actions. At least one person in the comments claimed success.
Just run the following commands to uninstall the old system apps if you use a custom rom.
adb shell rm /system/app/GoogleQuickSearchBox.apk
adb uninstall com.google.android.googlequicksearchbox
adb shell rm /system/app/VoiceSearch.apk
adb uninstall com.google.android.voicesearch
Then they will install just fine from Market (from the US Market). MarketAccess set to TMO US will allow you to find them.