How can I give my Photos a 1950s, 60s, 70s etc. look?
You could also play with another online application: http://www.picnik.com/
It lets you edit any image, adding various cool effects... it's worth a try!
Also, check out following web app.
Wanokoto : Make Photos Look Old Style
The above answers mentioning Sepia are great. Trial and Error are also good methods. Take the picture into any image editing software of your choice (preferably one that has preset filters like Sepia Tone, Black and White, Grain, etc. because MSPAINT probably won't do you any good.) and mess with the photo.
Any photo software you use will have a setting for Sepia. Use that and it will give the photo an old bl/brown faded loook.
mmmmm, that depends on what software you are using and how good you are using them. You have your very basic tools, such as changing the tones of the image to a more sepia tone, or creating wear and tear on it, and you can use Photoshop to create very realistic aging to it. What software were you planning on using?
Testing an Answers comment post.