Disclaimer: I'm mostly going to be talking about tabletop RPGs, since that is where most of my experience with Deaf participants is. Some of this advice may work fine for a performing RPG, but I have little to no experience with that. I'm also ignoring play by post- Suffice to say that you can play RPGs online in a written form, and therefore entirely sidestep any trouble with your deafnesss.
Four quick questions- How deaf are you, how well do you speak, do you sign, and if so how many other signing individuals are in your area?
One of my gaming groups has two deaf players. One is simply hard of hearing, and besides can lipread and speak so well it was a month before I actually knew he was HoH. We tend to treat him the same as other players, though we have gotten into the habit (after he asked us) of raising a hand when we're about to speak. (Offtopic, but I liked how this reduced background chatter so much I've done it in gaming groups of all hearing participants if they're being too rowdy.) We make sure to stay facing the center of the table, so he can see our mouths, and that's pretty much all he needs.
The other player has much worse hearing. He can't speak intelligibly to the rest of us, and cannot reliably understand us. He can lipread, but finds it difficult and unreliable. Fortunately, the DM (Dungeon master- the person "in charge" of a roleplaying game, and the one who does the most communication of the group) has a limited fluency with American Sign Language, and one of the other players minored in ASL. When the DM speaks, he signs along with what he's saying. When the players are speaking (remember, we go one at a time due to the lipreader) the signing player interprets, and translates what our deaf player says. The translations are often of the quick and dirty sort (Neither the DM nor the translating player are ASL translators- they have about a year's training in ASL) but it works. Some things can be pantomimed easily- "I hit the orc" is easier to understand if you point to a miniature and mime swinging a sword. Some gaming jargon doesn't have a sign, but everyone seems comfortable with making up homesign. (Natural twenty is the movement for born with a 2 in the primary hand and a 0 in the off hand, for example. Orc is the sign for Angry, with an O held near the face) In a pinch, we write down what's happening on a sticky note and pass it around.
The easiest thing to do if you sign is to find a group who also signs and is interested in role playing. Your deafness is only an problem to the extent that it impedes communication. If you can can find a group that can easily and quickly understand you, then you can play just like anyone else. Even if not everyone in the group can sign, if most of them can then they can translate back and forth. (Note: This is far easier with at least two or three such interpreters. It gets tiring faster than you think if you aren't used to it!)
If you don't sign or do not have a population of signers in your area, but can understand and verbally communicate easily with hearing people, then you can still roleplay easily. I strongly suggest playing a game that using miniatures and a board to show where people are even if the game does not recommend this- some groups do not use miniatures, and you will have an easier time seeing where everything is, and they will be able to easily see where you want to be. If you don't want to shell out for fancy minis, Legos work just fine.*
Ask the players to speak one at a time. This is good form anyway even for all hearing groups, and will make it far easier for you or a translating player to catch everything. Have them use a visual signal (such as raising one hand) when speaking, and if you have a signing translator raise a hand to get their attention.
If you have difficulty being understood or understanding, I highly recommend creating signs for common terms. Even if you're highly verbal, some things like "Maneuver" or "Fortitude Save" or "orc" might be easier if you have some kind of shorthand for them.
Bottom line is, you can play RPGs even if you're deaf- there really aren't any audio cues you need, just simple communication. While deafness is a disability, you can order a lunch at a restaurant, you can communicate with peers at work or school, and you can certainly play RPGs. Just find a group that's willing to go a little extra mile to communicate with you- and honestly, that's something even hearing people need to do sometimes.
*D&D fourth edition is actually really good for this-the high use of minis plus power cards means that you can basically just show the DM the card, point at the target, and if necessary shift the mini where you want it to go. While you may miss out on descriptions or dialogue without other communications, I imagine you could probably play the tactical part of 4th ed just fine with no other communication channel.