I found a dog today...

There I was hanging out in an alley today minding my own when this little dog walked up and sorta just jumped in my car. No kidding. It was kind of near a major street with a lot of traffic and I felt like he would probably get hit if I kicked him out...then it started raining so, after asking some neighbors who said they saw him running around all day in the alley sniffing stuff, I took him home. Like a sucker. No collar or tag. Pretty dirty. I think he looks kinda like a jack russell terrier but i'm not sure. Cute, white with a black patch over his eye. Potty trained. I plan on making some flyers with a phone number and posting them around the neighborhood (this was in Kenwood, St. Pete by the way-do they have a blog over there?) but I'm pressed for time as I'm leaving town this weekend so I really can't keep him right now. Does anyone out there want a dog?
Update: The Humane Society wouldnt take him. No microchip. He's going to Animal Services if noone takes him...