yes! seconding the epsom salts tip. tomatoes are super sensitive to magnesium deficiency.
steer manure can be bought in sterile bags at any of the big box stores come spring and summer.
once your plants get going and are about 16 inches high, be sure and leaf the plants up about six inches from the ground so that you don't get dirty water splashing up on them when it rains...tomato leaves are fuzzy, and they catch soil-bourne diseases really easily because the little hairs trap the dirty water and don't let it run off. this will also stress the plants a little bit and make it produce a few more flowers!
god, i love tomatoes. if i could only grown one thing that would be it!