1) Cleaning - yes, a little soapy water and they should be good to go. Also use a hobby knife (metal) or sandpaper (resin) to remove the flashing.
2) Gluing - glue first. For the metals, I use super glue. Get the liquid and keep it in the freezer. An open tube lasts for years in the freezer. I don't know what to use for resin... though I suspect super glue would work there too. Just a little bit will do.
3) painting - here's what I do
a) priming - get a can of krylon spray paint (I like light gray, but white or dark gray works too)
b) build a spray box out of an old cardboard box (hit up the local home improvement stores for a dishwasher or oven box)
c) LIGHTLY spray the models (lots at once) making sure to get every surface. The paint should be dry by the time it hits the model. You DO NOT want the paint to run. Hold the can far away.
d) As far as the other paints... that all depends on what you like. I've used testors, GW/Citadel, and craft paint. I liked Citadel because of the wide variety of colors (I don't mix up my own colors well), and really, they aren't that pricey. The problem is that the paint pots tend to dry up. If you get tubes of acrylic paint from a craft store (or online like Dick Blick), then you can get tubes that won't dry out. Usually thinner paint works better for newer painters. I still prefer it.
e) When finished, coat with a spray on poly... I prefer a matte finish, but you might like high gloss.
4) Guides... this is a good one with equipment lists, and techniques http://www.how-to-paint-miniatures.com/miniature_painting_necessary_equipment.html
Hope that helps.