Another question, Being new to veneering, I have read many articles in woodworking magazines and most say to either use a veneer press or vacuum system to press down the veneer. but one article said you can wet the veneer, then roll glue on the veneer & substrate, let it sit for an hour the "iron" on the veneer. Will this work??

How big are the pieces you intend to veneer? If they are large (I wouldn't iron veneer more than 2' x 2') then I wouldn't recommend the iron method. As soon as you dampen veneer with moisture in the form of water or waterborne adhesive it will curl and become hard to handle. Paper backed veneer is easier to work with this method.
Not all PVA glue is heat resetable. Do some tests to get your technique down and see if your glue will work. I have thinned Titebond a bit to lay a thinner coat on the veneer and substrate. When done right the bond is as good as a press applied one.

+1 on the small pieces, I wouldn't try it on anything large. Also, depending on the species and how wet it gets, the iron can dry out the veneer so fast that it cracks along the grain lines. I haven't seen it happen often, but I have seen it happen.

This method is not the best. White glues are an evaporative cure glue and the best glue line is the first cure. Drying and reacitvating these types of glue with heat weakens the glue strength by 50%. Some issues when you are doing larger pieces is how long to do you keep the iron in one place, how do you get consistent, equal pressure and what type of pressure are you actually getting.

Yes a lot of things can go wrong: too much glue leaving pockets of glue, too little leaving bubbles, too hot an iron will discolour the veneer and degrade the glue,etc.
On the other hand the technique allows you to apply edge veneer to curved surfaces and veneer to assembled components where it would be otherwise impossible.
It isn't an alternative to proper pressing but a good arrow in your quiver. I have had good success with it. My mantle has a decorative geometric patterned veneer edge that has stood up for a dozen years of fireplace heat with no adverse effects.

Thanks for all the advice. It gives me more confidence before I tackle all the projects. But now another question..... In cherry, it developes a nice patina as it ages on furniture. Will a veneer do the same thing?? as I will be using solid wood in some places & veneered in others and I want hem to match as it ages.

The short answer is yes, it will patina. I commonly used veneered panels in 5-piece doors and both would change color. There may be a bit of variance in the rate of change but I am not certain of that. I have noticed it some, but that could be all the veneer came from one tree and the solid came from many different trees. Each piece of wood reacts slightly differently.

One of the issues of that iron on is that the PVA will curl the veneer because of all the water absorption on one side of the veneer. Veneer will always be a slightly different color because of the steam and water soak before the veneer peeling and because of knife checking in the peeling procedure. Clear coat only doesn't show as much difference as dye staining.