I had my first male-male experience in a bathhouse (565 Beaufort, which is regrettably now closed). There's another one in Perth still running, Steamworks (
http://www.perthsteamworks.com.au/) which I haven't personally been to. The advantage is that you don't have to worry about wondering if the guy you're checking out is a) actually into guys, b) out for sex tonight and c) interested. In a bathhouse, a) and b) are an emphatic yes and c) is usually obvious. The etiquette is that when you arrive, you get a towel and (usually) condoms and lube. Take your own condoms if you've got a preferred brand. You strip off in a locker section and wear just the towel around the place itself. Then you can either cruise around and check everyone out, or watch some porn in a viewing lounge, or check out some action live, in the flesh, or just hang out in a comfy chair or hot tub and wait for someone to come along.
There's a good guide here
Link is broken,so has been removed but the short version is:
1) Play safe at all times. Always use a condom. Always. If you never, ever let your safety slip out of your mind then you can relax and enjoy the sex.
2) If you get approached and aren't interested, say no politely. They'll back off.
3) If you get a polite no, don't be rude - smile, be polite and back off right away.
4) Always wear a condom! So important, it shows up twice even in the short version.
It's not considered rude to hang around for a while watching and seeing if it's really your thing, but if you do go into a "private" area with someone then it's polite to let them know you're new at this.
Hope this helps, and enjoy yourself. As posted above, remember that same-sex sex doesn't make you gay - it just makes you open-minded. Plus the blowjobs are fantastic, best I've ever had (sorry ladies).