If you are planning to travel on public transport in Spain, then you may find the following websites of interest. Totally Spain can assist with the purchase of both rail and coach tickets if they are bought in conjunction with a holiday. We do not book rail and coach tickets only.
This is the web page for RENFE, the Spanish rail network, where you can check timetables, prices, etc., if you are planning on travelling by train.
ALSA is the biggest coach company in Spain, with a wide choice of routes throughout the peninsula. You can check timetables, prices and buy tickets online.
CONTINENTAL is another major coach company in Spain with many routes between cities in Northern Spain (Bilbao, Vitoria, Santander, Burgos, etc.), Madrid and the south of Spain (Sevilla, Granada, Málaga, etc.)