Hey!
IBGP is shortened for internal BGP. BGP was made to use as a EGP.
When a BGP peer is advertsing a prefix it learned, it must know the next hop address. If not it will not advertise the prefix. To use IBGP u'll need some fullmesh design, hence all peers must talk to eachother.
You must use some other routing protocol so that all BGP peers can find eachother (ospf, static...).
Some good WAN design is to use OSPF/ISIS as a IGP for the links and loopbacks. Then use IBGP and advertise all LAN address. This way u will have good convergence and stable database.