That is wildly incorrect. The Spurs will be at ~35M in 2010 with only TP, TD, Hill and Ian if they pick up his option. If the salary cap is ~58M like this year, that would leave the Spurs with 23M to spend. If they extend Manu at the same pay he is receiving now (if he gets an extension, you have to assume he was healthy, and in that case will not be getting a pay cut) which is ~10M, that leaves the Spurs with 13M to spend on 10 players. Bosh at 90M over 6 years would = 15M per year and the Spurs do not have that and they would be over the cap with only 6 players on the roster.
As you can see, that is not going to happen. Even if the Spurs do not extend Manu, they will have 23M to spend with 4 players on the roster. If they give Bosh 15M they will have 8M to spend with 5 players on the roster. There is no realistic scenario in which Bosh can come to SA.