In the Google+ app, hit Menu, then Settings. Scroll down to Photo settings. Check the box that says Turn On Instant Upload. Adjust the other upload settings to your liking (uploading on mobile data is not the default, so if you want to upload at all times, make sure you set it to upload through mobile and not just wifi).
Thanks; Your tip got me on the right track. I tried what you said, but the only option under "Photo Settings" was the messsage "Instant Upload is unavailable." It then told me to enable Instant Upload in the Accounts and Sync system settings. But... there is no option for that in the accounts and sync system settings! Google was already turned on. But, on a hunch, I long-pressed the Google sync account, and Instant Upload was an uption under that.
I'll have to give it a try and see how it works........Jake\
Edit: Yep, it worked perfectly! Thanks a bunch.....