When my DD took the Iowa Test of Basic Skills this spring, one of the sections where she scored a bit lower (though still very respectably) was on capitalization. The grammar programs we've used haven't really gotten into this topic all that much beyond the basics (i.e. proper nouns, the pronoun "I", the first word of a sentence, etc). So I went looking on the 'net for some capitalization worksheets. I came across a great site with lots of different free Language Arts worksheets. Be forewarned that the answer keys are NOT included, but I personally found I didn't really need a key for the worksheets I have used so far.
Thanks Mrs. Hatzigeorgiou, whoever you are! :-)