In the case of Excel's "Linrar Programming", it is an instantantation of regression analysis. "Linear programming" is specifically a subset of the larger term regression analysis. A common technique in regression analysis is generate the function (the "least squares fit"

of a set of points to a "type" of function, and then solve the function for the desired result. The "Linear" in the case of excel refers to the type of function being fitted - a straigh (or "Linear"

line.
Of course, the least squares fit code is available in many resources, the process utilized in excel (particularly the consraints) are less readily available.
While I know of no VB add in for "Linear Programming", I have used many Excel functions from within VB. This technique is accomplished by adding the Excel Library as a reference, and 'decoding the arguments' required by Excel to some recognizable vb format. Usually, these take the form of either arrays (for ranges) or individual variables for individual cells. However some few functions do not appear to be ammenable to this approach.
I have worked toward converting an older version of the more general regression analysis for use as a VB program (or add-in) but have not completed testing of the program as a stand-alone aplication, and have not even considered the issues involved in the conversion to an ActiveX control. Considering the existance and 'popularity' of Excel's implementation, I do not believe there is a large market for the more general soloution, so the priority of my version is rather low. In fact, your's is only the second 'request' for an alternative I have seen this year.
There are other tools on the market which have extensive analysis tools and include some general regression analysis capabilities, however they are not free (or even 'cheap' for individual use). SPSS, and MathLab come to mind quite readily, while TkSolver is -I think- a bygone product of the late '80s or early '90s.
MichaelRed
m.red@att.net
There is never time to do it right but there is always time to do it over