cookie_chef had some questions, which I will try to answer.
1) The importance of an agent and how to go about finding one.
I do not think it's necessary to have an agent for short stories. It does help to have name recognition with an editor, but my first sales were through slush; I hadn't met any of the editors to whom I submitted. Also, the pay rate is low enough for most short story markets ($50-$100) that I don't think the agent's percentage is worth it to either you or the agent.
For novels, I'm told it's better to have an agent to negotiate the contract, but some people sell the book to an editor then acquire an agent, when your writing has become a known quantity (you've already sold, so it's likely you'll sell again, plus the agent gets their 15% or whatever without having to shop the book around themselves). However, in erotica markets, I've noticed many markets don't require an agent for you to submit, so I would go ahead and submit instead of waiting until you do or do not find an agent--because if you send nothing out, you definitely won't sell anything. And if you sell things, you get a track record and you're more likely to interest an agent in your work.
My agent tale is unusual. I shopped a historical novel to several agents, and some of them read the manuscript, but none of them took it on. Then the co-editor of an anthology to which I'd sold a story, who happened to be an agent, asked if I would prepare a novel proposal based on that story. I did so, and thus have an agent, of a sort. However, I have not signed a contract with her, and won't unless the proposal sells and I have to complete that novel. If the proposal doesn't sell, we may or may not part ways. I don't know if this experience is typical or not.
2) Resources for erotica writers (networking and otherwise)
My favorite website for calls for submissions, networking, etc. is the Erotica Readers' Association. I haven't done much networking there, but their calls for submissions are always up to date and pretty thorough.
It's also helpful to look at blogs and LJs--check out, for example, sacchig, cecilia_tan, julesjones.
3) The road to publication (what to expect, time involved)
I hate to say "it depends," but it does. Some anthologies come out within months of the deadline for submissions. Some take a year or even two years. One of the larger presses producing erotica anthologies is Cleis. The submission deadline for Best Lesbian Erotica is end of March/beginnning of April. Usually, you get an email around June letting you know if you made the first cut, then another in a month or so to let you know you're in the actual anthology. The anthology is published in December. This timeline can be roughly applied to most of the anthologies that come out annually from Cleis and Alyson Press. Fishnet Magazine publishes fairly quickly after the story is bought; I think their rule is within 90 days, but am not sure, will have to check the last contract from them. If you sell to an anthology which does not yet have a publisher, you could be in for a wait of several years, or never see the anthology in print at all.
4) Critique groups
I think critique groups are useful just to keep your sanity. You spend a lot of time hunched over a computer, alone, writing; it helps to get out and talk to other writers who can understand what you're talking about. Also, a group can mean you make more contacts, obtain more calls for submissions from different sources, etc.. Finally, it's nice to get feedback, especially good feedback, just to keep your spirits up. If you're writing for someone, as I and some fellow workshoppers were discussing on Saturday, you don't feel so much like "what's the point?"
I critique some of my erotica, but not all. Sometimes it depends on the deadline; I may not have time to wait for the next workshop before the story is due. Sometimes, the story is what it is, and I don't think it needs any more work, or perhaps I don't want to invest any more time in it. I've sent those stories off, and they've sold. I usually do at least one editing pass on a printed manuscript of my draft, sometimes two or even three; but lately it's been more like one. I think my initial drafts are simply cleaner than they used to be.
I tend to submit stories for critique when I'm not sure what to do with them; where should the plot go? Are these characters interesting? Does anyone else have a better idea? Sometimes, they do. "Poppet" was one of those.