Storing Procedures / Transactions

Mabye I made myself not clear enough- sorry for that...

What I want is having a statement like:

PROCEDURE MyProcedure(Value1 int, Value2 text, Value3 varchar(30))

BEGIN

   ---check if something is valid

   ---compute something

   ---store values I got via THIS query and put them in table A, B and C

   ---see wether everything is ok

COMMIT;

...which I execute from a client like: exec MyProcedure(Value1, Value2, Value3)

Hope someone can talk me through this… ;)

Thanks in advance,

Chris