Seconding Hard Candy's Glamoflauge -- I don't have freckles, but my friend does and I actually gave her my concealer for that purpose, and it works really well, as it's supposedly for covering tattoos. The only downside being that the colour range is very small.
"I would like to be the air that inhabits you for a moment only. I would like to be that unnoticed and that necessary." -Margaret Atwood