The problem becomes...can you? Most Jewish dating sites have restrictions on who is "eligible" for their services, and that often includes converts. A dating site aimed at (or open to) liberal Jews may still require a customer to be a "halachic" Jew, whether that standard is reform, conservative, or orthodox. Even if you have already converted, a site with orthodox standards may refuse to approve the profile of a person with a conservative conversion. This used to make me furious, so I can understand if it makes you angry. Since it doesn't affect me anymore, I'm more open to the "Well, it's a private business..." argument (human nature, I guess!).
The problem is that the sites may not tell you their conversion policy. That's what I object to strenuously. They let you spend three hours filling in your profile, it gets sent for approval, and then you get an email rejecting your profile "because you're not Jewish." One service was kind enough to call me to give me the news in person, as though it isn't hurtful enough to read. After twice being treated that way, I gave them a healthy piece of my mind (as did several others around the same time, I later found out). Hopefully you won't suffer the same indignities that many of us have, but there's still the potential. If you want to find the website's policy, it is most likely in the Help section. You can also contact them before making a profile to save you the trouble.
As I have said many times before, I do NOT recommend dating during the conversion process. However, I know better that I can't stop you from playing with the websites (because I am SO guilty of that).
JDate: Ahh, the old standby. Considering that it offers "willing to convert," "not sure if I'm willing to convert," and "not willing to convert," they'll take anyone and everyone. However, you may not like the choices available there, especially if you're a woman. I used JDate in college ("willing to convert") and was surprised how many used the site to look for one-night stands. Apparently, it made their mothers happy because "If you're going to do one night stands, do them with Jewish girls because eventually you're going to like someone the next morning." I'm told this issue is less of a problem post-college. I do know people who have used the site with great success, even a few orthodox. However, if you're in the orthodox process and using JDate, you will get some tough questions from your rabbis. (The KvetchingEditor wrote about a similar situation on her blog: Orthodox Conversion: Beth Din First Meeting.)
Frumster / JWed: The old site Frumster is now known exclusively as JWed. For a while, both sites were available but drew from the same profile pool, from what I could tell. JWed, after many years of not doing so, addresses conversions in its FAQ. It requires "a universally-accepted conversion," defining that as "a conversion to Judaism which has been completed in full and which is recognized by all Jewish streams including the Reform, Conservative, and Orthodox movements." In other words, an orthodox conversion. Why they can't just come out and say that confuses me, and I believe it may give false hope to liberal converts who aren't as aware of the controversy. It also makes me laugh that they believe any conversion is "universally recognized."
Saw You At Sinai (SYAS) / YUConnects / JRetroMatch / J-Junction / Sasson V'Simcha Connections: I met my husband through SYAS, but I ended up there because I like their process much better. I don't see a conversion disclosure on their website, nor is there one when you fill out the profile. However, I know from experience that, even though they gladly work with non-orthodox singles, they do not accept non-orthodox converts as members. It's misleading because they ask you to name your beit din, etc, and you are only notified later when they can't verify that your conversion was orthodox. They need to be more upfront about this to save people the trouble and embarrassment.
In short, it's best to not even bother until your conversion is done, even for curiosity's sake. It might cause more harm to your self-esteem than the dreamy procrastination is worth.
Do you know of any other Jewish dating sites?