i'm not actually sure who to send such things (review requests) to. there's no master list of people who review indie games afaik.
I should add that I rarely go looking for or begging for reviews when I send stuff out. It's boring and I tend to mail anyone who I think might just be interested in looking at the game even if they won't cover it. If that makes the slightest bit of sense.
For me, it's not *just* about soliciting for copy - although I find that's rather easy to come by with a little grunt work, it's about getting noticed. They might not cover your current title, perhaps it's shit, perhaps it's bad timing and landed in the middle of major E3 coverage or something but if someone can make a mental note at the back of their head somewhere about you or your game, it's a win. Next time round, you might just need that y'know?
another thing i find is that getting the first few reviews is slow and difficult, but once you get those, other people review it just as a matter of course, since if site x and y did it, site z wants to cover it as well. journalists tend to go with the herd instinct sometimes, and think 'all those sites reviewed it, so we have to too or we'll be missing a story'.
Oh aye, never underestimate the old adage of once you've got coverage, it's easy to get it to snowball - on the proviso that you're doing something or saying something interesting enough for folks to cover it in the first place.
I think it's really about as difficult as you make it, rather than being an especially difficult or slow thing to do. It's a bit of a game and worth treating not just as work but a bit of fun to boot. It's not really that hard to get coverage, and by no means should you isolate yourself to whether someone covers indie games or not - yours might be the one to break the mould! What is difficult is coming to the realisation that it's not difficult. Scary barrier at first but once you break it down, walk in the park.
Aside from wot I do, I also get a fair few review requests and solicits a week. And you know what? Most of them I find it fucking hard to care about. They're dull. It's either some kid in his bedroom crafting a near corporate level of press release (why, Lord, why?) or someone just mailing me a short message along the lines of "Hi, I'd like it if you could review my game. Here is a link." only sometimes without the link. Just for bonus points.
Or my personal favourite "perhaps you'd like to interview me?" - umm, why would I want to do that? At least if you're going to ask give me good reason to want to!
Given my time is finite and I've got a ruck of stuff to get through, that's not going to get anyone to jump the queue to the top of my list. It's not going to make me run off and say "wooh, I've gotta check this out NOW!". Which is what you should be aiming at doing if you want me to review your game.
Prime example. Nathan Fouts of Mommy's Best. One of only a couple of devs who contact me through my personal email on a regular basis. I'll cover pretty much most things he sends my way because he's interesting. He's got interesting things to say and well, even if I'm not the worlds biggest fan of Weapon Of Choice, it's a damn site more interesting to discuss with him and write about than most of what I get in my inbox. He's got an automatic win by that very virtue.
Interviewing Cliff a few years ago was an absolute pleasure. It was a bit of a promo piece (and sadly lost from the net now although I'm sure I've got it around somewhere) and y'know, my aim was to get the word out a bit to an audience that wouldn't normally notice him and he's a great person to interview. Regardless of whether you agree on his stance on stuff, he's fascinating. He's a character and he's not afraid to be himself in interviews. Brilliant!
My advice here to folks is to have some faith in yourself and your own skills and most of all, convey that to me or whoever you're contacting. Make me truly believe I need to see this game now. Sitting on both sides of the fence both as someone who does reviewing and someone who gets reviewed, I can see the value. Don't hit me with generic hyperbole, bullet points or whatever, make me believe in you.
that said, i don't actually think reviews are that important. most of the traffic to my site comes from search engines and people randomly clicking on mentions of the game on forums or blog comments, not from reviews. i don't even think the majority of the gaming public even reads reviews anymore; i don't read them myself.
Other people are eternally fascinated with other peoples opinions! There's more of a spread now with the internet but reviews are still a valuable tool, perhaps if only to have something a little bit extra to use in your marketing canon.