Nar it's not possible to get rid of freckles. You can get rid of moles tho...
To let them fade, most important is to stay out of the sun.. apply moisturiser+sunscreen spf15+ everyday before you walk out of the house..
And the lemon juice thing.... vitamin C just helps to peel off the top layer of skin so it looks healthier... you can do that... but dont do it too often since your skin needs time to heal and repair itself..
Oh, and to prevent freckles... apparently alot of antioxidants help... stuff like actual green tea (not the sugar lipton crap), umm tomatos, capsicum, etc...
Yeah that's all I can think of atm... =]