calling one stored proceedure from another

yet another question unfortunately

I have now created a stored proceedure that has a return parameter, not i am unsure how to call it from another proceedure,

ie
say i have select projectid, project name from projects into temp from projects.

how can i then loop around all the rows in temp, to call my stored proceedure for each record?

in vb i would have created a function like my stored proceedure, then picked up a recordset, looped around it and picked up the return value for each row.

can this be done for sql?

I am trying to do something like

for each record in #temp (projectid, project name) find the stored sprceedure value

so my end result will look like

projectid, project name, @.storedproceedure return value
lprojectid, project name, @.storedproceedure return value
projectid, project name, @.storedproceedure return value
projectid, project name, @.storedproceedure return value

any help appreciatedLoops are inneficient and should be avoided and replaced with a set-based solution wherever possible.
I think what's really needed here is a user defined function (or UDF for short)!
I've knocked a quick example up for you to give you the idea.

IF EXISTS (SELECT type FROM sysobjects WHERE type = 'FN' AND name = 'gvFunc') BEGIN
DROP FUNCTION dbo.gvFunc
END
GO

CREATE FUNCTION dbo.gvFunc (
@.dob datetime
, @.curDate datetime
)
RETURNS int
AS
BEGIN
DECLARE @.age int
SET @.age = DateDiff(yy, @.dob, @.curDate)
RETURN @.age
END
GO

DECLARE @.myTable table (
employeeID int IDENTITY(1,1) PRIMARY KEY
, birthDate datetime
, fName varchar(10)
)

INSERT INTO @.myTable (birthDate, fName)
SELECT '1985-05-01', 'George' UNION
SELECT '1954-05-02', 'Timothy' UNION
SELECT '1968-01-29', 'Julie' UNION
SELECT '1986-11-25', 'Adam'

SELECT employeeId
, fName
, dbo.gvFunc(birthDate, GetDate()) As [Age]
FROM @.myTable

DROP FUNCTION dbo.gvFunc

Note to others... I know that I can't use GetDate() within a function - but why is that?