Saints and Bradford will appear in front of an independent tribunal on 12 July, with the hearing for Wigan taking place on 16 July.
Last year Wigan and Bradford were both deducted two points and handed fines for overspending in 2005.
But punishments have been increased and clubs now face a loss of between four and 12 points if found guilty.
Bradford chairman Peter Hood said: "Since March 2006, Bradford Bulls has kept the Rugby Football League in the picture as regards its salary cap position and has at all times co-operated fully with the compliance commissioner's investigation.
"Insofar as the detail of any alleged breach is concerned, Bradford Bulls reserves its position for the appropriate tribunal and in the meantime will be making no further public statement."
St Helens and Wigan have so far declined to comment.
Castleford, relegated from Super League last season, could launch a legal challenge if Wigan are found guilty.
The Warriors finished just three points above Cas after winning nine of their last 11 matches following the signing of Great Britain prop Stuart Fielden.
"We raised concerns at the end of last season about the possibility of this situation arising and, if a breach of the games rules has contributed to our relegation, then it will leave the club and its loyal supporters feeling very bitter," said Castleford chief executive Richard Wright.
"We are watching the situation very closely and will, if appropriate, consider what steps we may take."
Clubs are permitted to spend no more than 50% of their income, up to a maximum of Like