Bus is easiest way to get there. One can simply walk into a travel agent's office and book the bus tickets. Buses are frequent, very comfortable, and cheap. For a luxory bus with reclining seats, movies, and bingo we paid around fifty soles.
There are early morning (7 am) and afternoon departures from Lima to Hotel Paracas direct., with stops at Chincha, Pisco (town-terminal) and Hotel Paracas, and on to Ica Hotel Las Dunas. Trip takes about 3-4 hours. From the Hotel Paracas there are afternoon buses back to Lima and also onwards to Nasca. Ormeño buscompany recommended, their Royal Class service. Lima-H. Paracas around € 20 one way ticket. Cruz del Sur is another good buscompany. Safe and reliable. Went with Cruz del Sur in january 2007 and liked it more than the Ormeño service.
See also my Peru and Lima-transportation page for more info and websites.
Info January 2007
In Ica, Pisco or already in Paracas you´ll find organized tours to the Ballestas islands. the tour take some hours, you need warm clothes, because the wind is quite strong and you won´t leave the boat, it´s forbidden to enter the islands (for tourists at least).
So don´t believe, the warm sun will keep you warm.
The Royal Ormeno Buses gives transportation between Lima and Paracas. The journey takes about 5 hours.