The actual bill can be found here: http://www.legislature.state.oh.us/bills.cfm?ID=128_SB_243
From the looks of it, they bill is pretty specific in discussing hybrid embryos, and it specifically allows "(1) Research involving the use of transgenic animal models containing human genes;" and "(2) Xenotransplantation of human organs, tissues, or cells into recipient animals, including animals at any stage of development prior to birth, so long as the xenotransplantation does not violate a prohibition in division (B) of this section;"
Any violation of the law is only a misdemeanor, so its meant more to be symbolic then to prevent any ongoing activity.
While grafting and transgenics are fairly common now, I don't think there have been any official reports yet of anyone trying to create a true human/animal hybrid. The biggest hurdle to true hybrids might be the number of chromosomes - while humans have 46, most other species do not. even gorillas and chimpanzees have 48. Source: http://en.wikipedia.org/wiki/Chromosome#Number_of_chromosomes_in_various_organisms