I dont use eagle and it barfs in altium
If you are using Altium you can just send the PcbDoc file, they don't need Gerbers.
I hope itead works out.... beyond a certain size, OshPark's prices becomes expensive. OshPark is great though for tiny and small boards.
I've used both iTead and LCBCart.
The proto services like iTead sound cheap and they are under the right circumstances, but I need 10 different boards done so I costed a panel with 10 designs as opposed to 10 boards done with iTead.
Result, MUCH cheaper to panalize the boards and use a professional fab house. $880 for 10 designs (10 boards each) from iTead, $673 for 10 panels each with 10 designs from PCBCart.
Rob