Despite all the information from lonelyplanet.com, it is really easy to cross Transnistrian border.
As Transnistria unrecognized, we can’t stamp the passports, so instead stamps we have registration. Very important that it is FOR FREE. And no one needs a visa. In the registration form among other information, you should put address of your staying, it can be both hotel and private appartment (for example address of your CS’s appartment). This registration form, which you fill out on the border, is valid for 24 hours. If you want to stay for over 24 hours in PMR, you should also do the registration in the city where you will stay. There is special department which are responsible for this – OVIR (in Tiraspol it is on Kotovskogo 2A str., from 9 am to 5 pm, on Sunday from 9 am to 11 am).
But if you come by train there is no Transnistrian border on the railway, so at once after your arriving you need to do the enter registration on the train station.
If you still don’t know where you will sleep in Transnistria you can put in registration form the address of hotel, but you may not stay there. There are some websites of our hotels/hostels: CityClub, Timoty Hotel, Tiraspol Hostel, Hostel of NGO “Common Home” …. I think it is enough names.
By the way, keep the registration form, ’cause you will need to show it to customs when you leave.