What digital SLR camera do you recommend under $600?

For under 600, your only options are a cheap Pentax or Minolta or something from eBay. On eBay, look for a used/ refurbished Nikon D50/ D70/ D70s or a Canon 350D, a.k.a. Rebel XT (but not the sluggish 300D)
Retail, the cheapest camera I can RECOMMEND is a Nikon D50 with the Nikon 18-55mm zoom. That's $649 at either www.beachcamera.com or www.bhphotovideo.com, memory card not included. Add $55 for a 1GB Sandisk Ultra ll memory card, and you're set for about $700.

i dont think one under 600 dollars exists unless you find it on craigslist or perhaps ebay

I agree with OMG. It is well worth expanding your budget enough to buy the D50. It is a camera and system that can grow with you.

Canon 350D

http://211.78.161.52/gdpageimg/canon-350...
or
price check
http://www.dpreview.com/reviews/specs/Ca...

all canons are great ,but I've used the Fuji s7000 for around two years now and taken approx 12,000 photos with it ( no kidding ) absolutely trouble free ,just about the perfect camera for portrait shots or scenes with a top of 12 Megapixels (interpolated )
and adustable 1 ,2 3, 6 M,pix ,it's a little slow on the button for high speed pics like motor racing but still does a great job ,
this model is now selling on Ebay for @ 拢200 Gbp ,worth a look !
Regards Paul Liverpool UK