I've always injected Sub-Q, but I know a guy on some of the muscle forums who swears by injecting IM if I remember rightly and he is a UK NABBA champion I think and seems knows his sh*t!
99.99 % of us who use GH use it sub-Q. You can take it IM, but I would do so only in conjunction with IGF, insulin, AAS, etc.
Green, yellow, blue or pink...doesn't matter. HGH is HGH, 191aa. Depends on your source, color means nothing. How many IU a day depends on the person and his or her wallet. Some use HGH to cut, some use it to bulk. There are several ways to use it. Post your age and all your stats along with what goals you are trying to achieve and I'm sure we can help you out.
/V
A few good ones I've heard of are Nutropin AQ, Norditropin, Humertrope, Genotripin. I've hear hygetropin is good value for money!