yup I have when I wasn't planning a gravy for a cetain dish but wasn't about to waste perfectly drippings. And yes lable it and use within about 3 months. I keep a freezer log so I know what's in there and for how long.
No kidding, Katie! I've done that so many times, thinking I'll remember what it is. Then, I clean out the freezer, and find all these frosty little Ziploc bags with indistinguishable blobs inside.
Fortunately, DH is in charge of the freezer now, and we no longer have that problem.