to the forum, Steve.
While some people have had success keeping bettas and guppies together, it is not recommended. Usually either the betta mistakes the guppies for other bettas and attacks them, or the guppies nip at the betta's fins. Tetras can also be surprisingly nippy (even neons and cardinals, which aren't generally known for it!).
To be honest, male bettas are best keep either alone, or with some small catfish (like pygmy corydoras), which don't have the long fins or bright colour to set the betta off.
One other point; you don't say what sort of algae eater you're thinking of, but do be careful. I'm not sure if you're aware of this but many of the 'algae eaters' either grow very, very big (common plecs, gibbiceps), or stop eating algae as they get bigger (Chinese algae eaters; these can also develop a taste for other fish's slime coats)), so do research thoroughly before buying, or you could get stuck with a foot long monster that attacks your other fish!
Will you be doing a fishless cycle, using household ammonia? This is a fairly new method of cycling and one that is very much recommended.
Hope all that helps and again, welcome