If you are looking to get some T-shirts personalized for work or for fun, I'd recommend checking out TShirtPrinting.net. They actually will do screen printing on everything from T shirts to hooded tops to sweatshirts to workwear. They have competitive pricing and a huge selection. They can also do any size order you may need. They've got a ton of cool designs and will work with you to get exactly what you want.
Madison is wearing one of their screen printed T-shirts (ignore that she's sticking her tongue out at us when I snapped the picture). I love that the T-shirt is of a good quality. It isn't thin and see through. The print itself looks good too.
If you need a screen printed shirt, TShirtPrinting.net is your one stop shop.