If I'm a 1099/independent contractor and I need to contract a sub portion of that work to another independent contractor, does that "income" get taxed twice? As in when I bill the work back to the client, lets say 1000$, and 300$ go to the sub for the work he or she performed, Do I get taxed on the 1000$, the (1000-300)=700$, or something else?
Since you say 1099, I'll assume it's in the US. :)
Think of your consulting operation as a small business. Businesses are only taxed on their profits, not their revenues. So you should only be paying tax on the $700 in the example you gave.
Note, though, that you need to be sure the IRS thinks you're a small business. Having a separate bank account for the business, filing for a business license with your local city/state, etc are all things that help make the case that you're running a business. Of course, the costs of doing all those things are business expenses, and thus things you can deduct from that $1000 in revenue at tax time.