What hasn't been adressed in this thread is - does the loss of data *matter*? JPEG is rather cleverly designed to minimize loss of data that would be visible to the human eye. Next, bear in mind that printing your photos at 3x5, or viewing them on a computer screen, means sacrificing a great deal of data no matter which format you start from. Those losses, plus the differences between printers or between computer screens, are MUCH more significant than the difference between JPEG and TIFF or RAW in almost every case.
JPEG does produce certain artifacts if you look closely enough - "ripples" parallel to sharp edges, for instance, and a loss of very subtle color differences in variable areas like sky. (These artifacts become extremely obvious if you pick a low enough "quality" setting.)
Note that "TIFF is lossless" is not always true - TIFF allows several different compression schemes. Check that your TIFFs are created using "LZW" (or "raw/uncompressed"). (LZW is very likely what you've got by default.)
Shooting in RAW or TIFF may be worthwhile if you're planning to do a lot of post-processing (making things visible that weren't visible in the original shot, which JPEG might have felt free to discard), or if you think you might do a very large print. As others have mentioned, you pay a price in memory used.
Film dynamic range is at least [CORRECTED: 12 bit, which is equivalent to "36bit color" in computer graphics], probably more. I hadn't realized digital cameras might have more range in RAW mode; I always thought lack of range was inherent in the current generation of digital sensors. [Edit: Dougpaul has made this a little clearer.] I'll have to try it and see if there's a visible difference (and whether it's worth the extra work).
Ditto to what others have said about editing photos - make the original read-only, and save any intermediate versions in a lossless format like TIFF or XCF. But don't forget to convert to JPEG or PNG before putting the photo online - nobody wants to wait ten minutes to download a photo.
Edit: to clearly answer the original question:
"If I wanted to use TIF do I need to configure my camera and shoot TIF's or is this done when (or after)downloading from camera to computer?"
Either is possible and either can be a reasonable choice. Shooting in TIF mode captures more details from the scene (but takes a lot more space in your camera's memory). Shooting in JPEG and converting to TIF on your computer protects you against losses during repeated editing, which seems to be what you're more worried about.
If you shoot in JPEG mode, your camera will sacrifice some details (though I've suggested that you aren't likely to notice the difference). See DougPaul's post. Converting to another format after downloading JPEG to your computer won't bring those details back. However, if you edit your files on your computer, each time you save your changes in JPEG you are losing a tiny bit more data. Depending on the type of changes, this can quickly add up to a visible difference when you edit (and save) a file repeatedly. So if you plan to do significant editing, it's worthwhile to convert to TIFF once the picture is on your computer, even if you shot it in JPEG mode. (Of course, if you know you are going to do this, you will want to consider shooting in TIFF in the first place, if your camera permits it and you have enough room on your memory card.)