Hey Jabi!
I will take a crack at some of your questions here:
1. Renting an apartment by yourself is relatively safe depending on the area but honestly not many people in my class do that. I know of one person who does (female) in a nice area and she loves it. However, it is quite expensive to lease on your own! It's still expensive in Dublin even with a roommate but that also depends on where you live.
2. As far as renting procedures are concerned, I don't know of any website or resources out there. From my experience, they are similar in nature to renting in other places such as the US. For example, the apartment I am in now was posted on daft. My roommate and I contacted the management company taking care of it, who arranged for us to come see the place. We decided we liked it and had to put down a deposit, plus pay the first month's rent. In addition, we had to set up a direct deposit into the owner's account for each month of rent. They don't do rent checks here it seems. Everything is electronic, which is less of a pain actually. You will find that is the case with other bills such as cable/internet, gas, and electric. My advice: if you find a place you REALLY like, offer to sign a 2 year lease if they will drop the rent further.
3. Another thing I find different in Ireland is that they bill you every 2 months for some services. We have NTL cable/internet (I don't have the bills before me since I am not in Ireland at the moment), gas is about 48 Euro, and electric I don't remember. We didn't get a landline and instead just use our cell phones. NTL offers alot of promotions in the fall to attract students and you can get things like 6 months of digital cable for free, no connection fees, etc.
4. Also, I forgot to mention yesterday that RCSI has a housing board on their website. Have a look at
http://www.rcsi.ie/medical_school/accommodation/ubb/cgi-bin/Ultimate.cgi