Inconsistant time zone handling

I'm storing datetimes in MySQL in UTC. I want to retrieve them based on date.

Here's the problem. Time objects ignore the time zone in to_s(:db).

>> Time.local( 2009,1,1, 0,0,0 )
=> Thu Jan 01 00:00:00 -0600 2009
>> Time.local( 2009,1,1, 0,0,0 ).to_s(:db)
=> "2009-01-01 00:00:00"

TimeWithZone objects preserve the time zone in to_s(:db).

>> Time.zone.local( 2009,1,1, 0,0,0 )
=> Thu, 01 Jan 2009 00:00:00 CST -06:00
>> Time.zone.local( 2009,1,1, 0,0,0 ).to_s(:db)
=> "2009-01-01 06:00:00"

All the to_time helpers return Time objects which have their time zone thrown away when used in an ActiveRecord query. This leads to problems when using to_time

Example:

>> Date.today.beginning_of_day
=> Fri Apr 10 00:00:00 -0500 2009
>> Time.zone.now.beginning_of_day
=> Fri, 10 Apr 2009 00:00:00 CDT -05:00
>> Date.today.beginning_of_day == Time.zone.now.beginning_of_day
=> true

>> Person.all :conditions => [ "created_at > ?", Date.today.beginning_of_day ]
Generated SQL => SELECT * FROM "people" WHERE (created_at > '2009-04-10 00:00:00')

Person.all :conditions => [ "created_at > ?", Time.zone.now.beginning_of_day ]
Generated SQL => SELECT * FROM "people" WHERE (created_at > '2009-04-10 05:00:00')

It would seem to me that Time#to_s(:db) should convert the time zone and/or to_time should return a TimeWithZone.