1,3-dimethylamylamine was once actually patented by a major pharmaceutical company back in the 1930's or 1940's as an inhaled nasal decongestant. I don't know if it was ever sold to the public though. Recently, the credit for its discovery goes to Patrick Arnold of Ergopharm labs. Supposedly, that is one of the main active ingredients in Ergopharm's succesful energy product Amp.
There's actually a good number of sites that sell it in powder or capsule form. Do not pay very much for it. It's extremely cheap. It works similiar to pseudophed, ephedra, etc. I personally think it's much better for focus and mental performance, rather than just raw energy. I haven't noticed any major crash on it. I love it for mentally demanding tasks. It's my favorite stimulant.
It goes by several different names, one of the most common being geranamine. Just be careful not to start too high. 25mg is a good starting dose. Titrate your way up.