*shrug* It would depend on *why* you are trying to get rid of the battlemap. 1) You can't use one because you are in a car or something. 2) You don't like 4E. 3) You are looking to "simplify" the rules. 4) You hate map tactics. 5) You want to speed up combat.
Generally speaking, it is much simpler to not change any rules. You just change the trigger for the rules. If your goal is tactical simplification or speeding up combat a simple change would be abstract distances by aligning the party and monsters into ranks of three. Put Melee skirmishers in the first rank, Defenders in the second rank and range attackers in the third rank. Do the same for equivalent monster types.
1) Party Range
2) Party Defender
3) Party Melee Striker
4) Monster Skirmisher/Lurker
5) Monster Brute/Soldier
6) Monster Artillery
It takes a move action to change to a different rank. With a double move you may change two ranks. A move and a charge changes two ranks. Anyone in a rank is adjacent to anyone in the same rank and a higher or lower rank for attack purposes. Monsters and PCs may be in the same rank. Each defender can keep one monster from advancing into or passing through his rank. Push, pull and slide changes an enemy one rank. One PC in a rank can get a flank for each other PC in a rank (i.e. every 2nd PC in the same rank gets a flank), same for the monsters.
For flyers, enemy flyers would go in rank 0 next to the party’s range attackers, PC flyers or allies would go in rank 7 next to the monster's artillery.
For area effects assume the power hits every even enemy in a rank or let them choose to hit one target. To spice up combat, every once in a while put a pit (or some other obstacle or hazard) in one of the ranks and let people attempt to bull rush or slide, push or pull people into it.
This was an example of abstracting distances. Remember a map is just an abstraction of relative distances. You should abstract whatever you don't like about the map in 4E. The advantage of this type of approach is you don’t have to redo all the rules because most of the time they all still work.