Here’s a handy list of publications to send stories to (thank you Bookfox) most of them in the US. Those who only accept postal submissions will want a SAE for a reply- which means finding US stamps (94c), messing around with International Reply Coupons (expensive and a hassle for all concerned) or contacting the editor directly and pleading that you are resident in the UK where the postal system is run by jackals and bears. The latter can actually work.
The list is by no means exhaustive, and I would question the inclusion of Epoch in the ‘Highly Competitive’ Section, as it’s just starting out and has a somewhat fresh-faced look (so says the old man of the sea). Otherwise it’s a good place to start, and will be invaluable in helping you to decide how bad you should feel about a given rejection.
http://www.thejohnfox.com/bookfox/ranking-of-literary-journ.html (you’ll have to paste this one in- it resists becoming a link).