Filmbase, located on the distinctive but unimaginatively named Curved St in Temple Bar is a resource for filmmakers. Most of the other reviews have hit the nail on the head, so I won't rehash what is said there, but here are a couple of addenda:
Filmbase have folders of headshots if you are looking for actors. You don't have to be a member or anything, you can just take whatever folder you want (Males 30-40 yrs old, for example) and head up to the coffee shop to peruse at your leisure. The coffee shop do a nice line in fancy lemonades, too.
And if you are a student and you would like to rent some lenses or whatever off them, it's better if you pretend that you aren't a student, as they will be more amenable to letting you have the gear. However, don't try and bullshit them if you are not confident in being able to pull it off, as they get bullshitters in a lot, so you have to be on top of your game in bullshit terms (DON'T wear a suit in order to impress them. Real-life media guys don't dress like that when renting gear. Real life media guys dress exclusively in North Face clobber; buy yourself some of that, hang around Filmbase, and watch the job offers come rolling in). read more