Anything from 24 hours to a week (on average) for the first round. We get over 200 subs a month now, but we have over a dozen readers.
I can't remember whether this is on the site, but our reading process works like this:
First round is a yes (Scored from 1 to 5, pass to 2nd round) or a no (returned to author). Second round fiction is read by two more people, who also score it 1 to 5 (1 being best). We try to be objective, of course.
Then, anything with a combined score of approx 7 or lower (e.g. 1+2+4) passes into the 'slushpool', which is where editors for upcoming issues select from. I think the slushpool-to-publication ratio is about 1 in 4, but we do let them go if they've been in there about 4 months (2 complete issues.) We let authors know at each stage what's happening - passed 1st round, passed 2nd round, then selected or returned. If you pass the 2nd round but don't get selected then that story is probably a very good one, it's just that nobody could find a spot for it.
The scores give editors a guide - for example, 1+1+2 is probably something with wide appeal, well-written, definitely publishable. We don't announce the scores to anyone, they're just an internal metric. We don't just base everything on scores, either. Most readers attach a comment or two - what they did or didn't like - depending on time.
We've been doing this for approx 4 years now, and writers seem to like the system. Of course, we'd love to publish everything sent in, but we can only squeeze 8-10 pieces into the mag every 2 months.
We're always on the lookout for interviews with SF/Fantasy people and non-fic. Unlike fiction, payment for non-fic is just a contributor's copy. Fiction is 1 & 1/4c per word australian (approx - we have an AUD$400 per issue fiction budget, divided by the no. words and no. authors. And min is $20, which means a few short pieces can affect the overall pay rate)
Finally, we're a non-profit cooperative, not a money-making exercise. There are 20 members who pay AUD$100 each per annum for the priviledge (see
http://www.andromedaspaceways.com/crew.htm), and it's really a labour of love for all of us.
I'd tell you to let me know when you submit, only it wouldn't make any difference ;-)