If you're biking the Ring of Kerry and leave from Killarney, this is a great stopping place. The hostel has a sign on the east edge of town, and it is a very welcome sight (especially if your bike trip has been blessed with as much rain as mine was). Cahersiveen is basically a one-street town, and the Sive Hostel is on your right on the eastern edge. It's not a large hostel, so the friendly faces become familiar pretty quickly.
The dorm rooms aren't locked, but they'll give you a front door key. You can store your bike in the courtyard out back (but you have to bring your bike around a block to the back - they won't let you bring it the few feet through the hostel). No lockers or laundry facilities are provided, and no phone (!) or internet (there's an internet cafe a few more blocks into town on the left, with a catchy jungle motif and hit-or-miss opening times).
There is only one shower for the entire place (well, actually there are two, but they're in one room with glass doors, so unless you're there with a friend, only one person can shower at a time). Even with a half-full hostel, you can get long lines, which can be irritating (and it's hard to keep clean or stocked with toilet paper). The toilet is in the same room, but they have another toilet/sink upstairs. There's also a balcony upstairs, which is perfect for watching the sun set over the bay. The staff was friendly, but not particularly knowledgable or helpful about the sights in town (several old forts, castle ruins, and the architecturally odd 'barracks' - you wonder, did they mean 'castle'?), or the history (childhood home of Daniel O'Connell - 'The Liberator'!).