Federal law still prohibits marijuana. A few states have legalized quantities of marijuana by anyone (some as high as 4 ounces), but of course this means nothing federally. A federal agent can still prosecute someone in a federal court for possessing any quantity of marijuana. The governments position has just changed on enforcing their power over state laws regarding marijuana by limiting access to certain federal funds.
Obama has mentioned moving marijuana out of the schedule one, to I think schedule two, which would cause the government to view it legally the same as they view Ritlin, amphetamines, cocaine, and PCP even. This would mean that the feds would acknowledge that there is some medical value to it, but still highly regulate it.
I looked up the drug you mentioned, and while it is THC, I do not think it is derived from the marijuana plant. It appears to be synthetic with a different chemical structure of THC derived from the cannabis plant. It is man made, which is why it is not classified schedule one like all forms of the THC from cannabis.
Interestingly enough, there is a lot more research that supports the medical use of marijuana than I knew about. Also, many of these medical benefits are lost in the synthetic version, marinol.
Anyone interested can view this article:
http://en.wikipedia.org/wiki/Tetrahydrocannabinol which is where I learned about marinol and:
http://en.wikipedia.org/wiki/Medical_Cannabis
talks about the uses of and legal status of the cannabis plant.