Hi.
I usually use comicvine.com to get my bearings around comics things. There's also Marvel Wiki which is probably also useful. You can read parts of a character's story if you jump in at a later point in canon and are confused or if you feel like jumping over a story arc you don't like. You can also find how the issues are bundled in volumes/collected editions in case you want to actually buy something.
For seeing what you should read and maybe downloading things check out
comicmastepost@livejournal. After the oneshots, team-ups, minis etc. it's pretty much in chronological order.
Starting from the beginning is probably complicated. Old comics are hard to read in my experience, but maybe you enjoy them more.
I started with Ed Brubaker's run, meaning Volume 5. But after a few issues Cap (spoiler) dies for a while and the story shifts to Bucky Barnes, so if you wanna read about Steve Rogers that might not be the best point to start... I made
a thread for Bucky a while ago actually.
I haven't read that many Cap stories with Steve himself or any of the recent ones with Sam as Cap. So I can't really help you that much. But Volume 5 is usually considered a good jumping on point, especially if you've watched the movies. I didn't find it hard at all to understand and I hadn't read a single Cap comic before that. I heard Mark Waid's run (Vol 3 #1-#23) also had some good stories, but I haven't read them.
I hope this is somewhat useful for you.
