A kind soul named Daniel Box has made it possible for we SLR users to get Instagram effects on our otherwise modern-looking and clean pictures. He wrote a series of Photoshop actions that simulate the effects. Here's one of my pictures of the Dead Weather in San Diego under the effects of Jefe.
I think the grey vignetting is a bit much, but otherwise it looks great.
The same action set contains Nashville, Earlybird, Brannan, Lomo-fi, Gotham, and several others along with some borders. If you are a Photoshop afficionado, you can tweak them. I always like really lots of Photoshop on pictures myself.
If you're not a Photoshop afficionado, you just hit the download button, open the zip file, double click the filename and Photoshop should open up and install it. Inside Photoshop, goo to Windows, then Actions to open the palette. After that, you just need to click on the name of the effect you want and press the VCR-style run button at the bottom of the actions palette. Or whatever the hell a palette is called in CS these days.
Odd that they changed the name of it but not the VCR-style buttons. It's one of those things like dialling and hanging up a phone that we'll probably be doing for years even though we aren't. When it's a physical thing, that's called a skeuomorph. No idea what it's called when it's just an old, meaningless concept.
Oh, I forgot. Mr. Box's box of goodies are on his Tumblog, here.
Added much later: Oh, look - PSKiss are selling an app for this as a plug in for Photoshop CS5 and CS6. Never tried it, so I can't recommend it, but since this is a popular post I thought I'd throw it in.