I found a link for you that might prove useful when you get the plants or seeds. http://saltaquarium.about.com/cs/man...a/aa110600.htm
Read through the whole 4 pg article, there's a lot of useful information there. I have some experience with them in saltwater, but not in fresh as of yet. They aren't cheap or easy to find around here. I plan to try the freshwater keeping of them once I find them, as I know they will soak up phosphate as much as nitrate levels, and this could prove useful in my breeding and fry tanks.
What I can
tell you about them is that they need to be at the surface with just the roots in the water, if you submerge them too far they die. They like natural sunlight, and when we put them into our saltwater tide pool surrounded by large plate glass windows facing east and south (the corner), they thrived. Most of the light they received directly was morning light from the east, and for a few hrs every morning they get full sun this way. We started them out as pods/seeds with limited root structure about 8 or 9 yrs ago and they are still there, growing strong and stand anywhere from 1 1/2 - 3 ft tall now. They're beautiful! When we put them into the tide pool they were put up high into the shelves, and set into some sand, supported by a rock or 2 if needed. The trick is to make sure that only the root system is completely submerged.
For decorating ideas, keep in mind that they would be good for an open top tank only. Corner structures work well for holding them steady. Be careful not to get too close to filtration units where the roots may grow and get tangled, burning out equip and damaging the roots, blocking intakes and such. Because they get so large, even tho slow growing, placing them in the back or as a centerpiece is typically best to allow you space for maintenance around them and light fixtures. Be careful not to get them too close to light fixtures and not too harsh of a light, either. Also watch temp... you don't want them to get too cold in winter months (not sure what your climate is like)... these are a tropical plant.
How big of a tank are they going into?
Good Luck, hope this helped.