I replaced my radiator on my 2007 double cab v6 4wd Tacoma last week in my driveway.
Easy job. 10 nuts to unfasten, and 4 hoses to unhook. Took about an hour and a half start to finish, but 30 minutes of that time was spent looking for a metric wrench that I put somewhere and couldn't find... If you do the work yourself, the only part you'll need off of the old radiator is the 4 screw mount/nut assemblies. They just pry off of the old radiator and install right on the new one.
Do the work yourself and save $250-300 in labor charges. It's a piece of cake to do.
Anyway, I bought my radiator at carpartswholesale dot com. They had the best prices I could find. I don't know the brand of the one I got...(I think it's CEF brand or something similiar), but it's the first one that pops up on the 2005+ tacoma page. It is a direct fit (make sure you get a 'direct fit' instead of a 'universal fit').
If you have a lot of miles on your truck, it makes sense to go ahead and replace the upper and lower radiator hoses while you are replacing the radiator. They are inexpensive and it's MUCH easier to change the lower one out while the radiator is out of the truck.
BTW, you have to check your automatic transmission fluid level when you are finished, because the AT fluid also goes through the radiator. Not a big deal, but plan on taking an extra 10 minutes to do that. I didn't have to add any AT fluid to mine after the change, but if you let the two small AT fluid hoses drop when you pull them off of the radiator, you could lose a substantial amount of fluid. If you plug them when you pull them off the radiator, you shouldn't have any problems.