I wrote this up for the camera club at work originally but it is a question I hear a lot so I figured I'd post it here to help everyone else out (assuming some people will start reading this in the future ;)
The stuff in Green is free, Red costs money, and Blue means it's sort of free because you may already have it bundled with your computer or burner.
For viewing just on pc (they're all FREE yay!)
FastStone image viewer even if you don't necessarily need a slideshow program this is a very solid image viewer that works better than the default windows one.
Irfanview another image viewer like the one above that also allows slideshow viewing except this one lets you customize the slideshow a little more instead of just playing all files in a folder. I find it a little more awkward that FastStone but some people really like it.
Picasa- This is a free program made by Google, it allows you to view your photos in slideshow form but also includes pretty decent image editing and a bunch of other "fun" stuff. I recommend everyone download this, its free and its constantly being updated with more and more stuff. Get it at http://picasa.google.com/ or if you'd just like to see what all you can do with the software you can watch a video clip explaining all the features at http://www.youtube.com/watch?v=rskC6c_5L1M
For burning DVD/VCD/SVCD slideshows to watch on your TV (Free... not so much, but you may already have some of these)
Windows DVD maker - I totally forgot about this one and its actually one of the best I've used, the best part is its free the only problem is that it only comes with Windows Vista
None - Just burn the photos to a disc and pop it in your player. Nowadays most players will actually play the pictures right from a cd or dvd, the only problem is that this only works if your photos are below a certain size since the player can only hold a certain amount "in memory". One option would be to use Picasa to create a gift cd and under photo size select "640x480" (800x600 or even 1600x1200 could work too), you may be able to just pop the disc right in your player or you may have to copy the resized files off of the disc and re-burn them onto a new disc so that it only contains pictures. Consult your DVD player manual for the most accurate information, normally it states what sizes it accepts and tells you if you should burn the disc in any special way.
Your current buring software - Just about any computer you've purchased in the last 8years or so should come with a burning program (or it would have came with your CD burner or DVD burner), the two most common ones are Nero and Roxio. Both of these will allow you to make slideshow CD's and DVD's that will play in most players. These are normally pretty decent programs that suit the needs of the average everyday person.
Trial Burning Software - The trial versions of most burning programs don't restrict the features of the program, instead they limit the burning speed to 1x and have a time limit. If you really need to make a slideshow though you can download a trial and use it to make a slideshow to burn to disc. Its not the best way to do it but if you're in a pinch its a soloution.
Ulead Pictureshow - I really liked Ulead Pictureshow 2 but unfortunately they are up to #4 now and you can't get 2 anymore. This is a commercial program that costs money but you can download a free trial to see if you like it or not.
Photo DVD Maker Professional - this is another one that costs money, you can download a free trial and check it out if you want. I found it wasn't too bad.
DVD Slideshow GUI - After much searching I did finally find a free program that will create DVD slideshows, I briefly tried it out and its not too bad. There are also a bunch of add ons for more transitions and effects, its all there on the website. Now being that it’s a free open source program it’s a little less user friendly but not too bad, I was able to create a basic slide show in just a few clicks.
Hopefully that gives you some options to more easily share your photos with friends and family.