Polarbear- A lot of people have freckles and love to show them off, which may be why you didn't get any replies! They aren't considered a negative beauty feature to many people. I actually have them myself. I was self conscious of them when I was in junior high, but by the time I hit high school I forgot I hated them! The process below is the best one to cover freckles, but if you have a lot of them you will likely not be able to cover them all. You don't want to continue adding cover up and foundation to the point it looks like you are wearing a mask.
However, to answer your question, basically you will use cover up/foundation. You will want a full coverage foundation-a tinted moisturizer will be way too sheer and allow your freckles to show. Apply foundation all over your face and blend carefully. Using your cover up, apply wherever you have freckles. Rather than just blending with a sponge or brush, dab the cover up with your (freshly washed) finger on everywhere you have freckles. Repeat until your freckles are less visible. Depending on how dark they are, you may not be able to cover completely but you can make them lighter. Finish up with powder to set the look.
Another idea is to go to a makeup counter for a consultation. Call first to see if you have to buy a product-some require a purchase from your makeover while some are free. Tell the consultant you would like to cover your freckles, and the consultant will show you using her products 1) what kind/colors you should be looking at and 2) how to apply them.
Getting rid of freckles is more complicated. There are many products sold that are not only rip offs, but dangerous. Basically, if it sounds too good to be true it likely is. Some of the lotions and creams sold have caused permanent damage to people trying those at home products. Research very carefully. A good starting point would be your dermatologist--ask him/her for recommendations. Laser freckle removal is expensive but more effective. Look at sites such as this.
Check with the American Medical Board, ask for references of past patients, research the doctor...this is your face, and for something as pretty as freckles it isn't worth ruining by going to a bad doctor.
Again, this site
has a lot of information on not only laser surgery but creams, treatments, preventing further freckles....just research as much as possible. To go along with that, make sure to prevent further freckles my wearing a high SPF sunscreen when you are outside now that summer is coming!