try Jewel in the Crown tour operator.
If you are booking independantly and dont get transfers to hotel, opposite airport entrance there is an official taxi office with set prices clearly marked out in the window, so you wont get ripped off.
Remember to take Boots roll on mosquito repellant and dont bother with the malaria tablets they will give you the runs for the whole holiday. If you get a chance to upgrade to an air conditioned room do it [ I cant remember if all rooms have A/C] we asked ahead [ have in-laws in Goa] for a fridge in the room for hubby's insulin and low & behold a big red fridge was already installed when we got there no extra charge.If you ask they will put a mosquito coil in your room to light when you go out in the evening and your room will be mozzie free all night or you can buy them they cost a few pence.
I hope you dont mind me adding this, pls tip the room boys etc when you leave they work for peanuts and save their tips to see them through the non tourist season when they cant find work.