I have several cats who require medication every day. Some of the meds I have to cut up into small pieces that aren't easy to administer. Other meds, like Flagyl, taste HORRIBLE and will make the cat foam at the mouth if he tastes them. For these, I have found "Pill Pockets" to be very useful. You just put the pill or pills inside this soft pocket and then shove it down the cat's throat!

They taste like a treat, so usually the cat doesn't mind. You can buy them at PetSmart or Petco. You can also get them for a little bit cheaper here:
http://www.revivalanimal.com/store/p/1897-Pill-Pockets.aspx