Hotels

There are more than 20 hotels in Kiev varying from the new "5 stars" to the old-"soviet style".

To see the list of all hotels in Kiev go to:
http://all-hotels.com.ua/city.php?city=1&lang=1
http://www.go2kiev.com/view/accommodation.html

Source: allhotels.com.ua, go2kiev.com

Apartments

Renting apartments is much cheaper than similarly furnished hotel rooms. Generally, apartments are completely furnished with bedding and all necessary furniture and equipment: one or two TV-sets, a refrigerator, an iron, a hairdryer, an electric kettle, a microwave, video or DVD, air conditioners (for heating and cooling), and a kitchen with all necessary utensils, enabling you to eat home-cooked food.

So if you want to consider this option here are some of the most popular web sites that provide this service in Kiev:
http://www.realrent.com.ua/en
http://www.rentkiev.net
http://www.rentapartments.com.ua/
http://www.rent-kiev.com

Ukrainian currency

The hryvnia (sometimes hryvnya; Ukrainian: гривня) has been the national currency of Ukraine since September 2, 1996. It replaced the karbovanets at the rate of 1 hryvnia = 100,000 karbovantsiv. The hryvnia is subdivided into 100 kopiyok. The ISO 4217 codes are UAH and 980.

Official Exchange Rate of Hryvnia against Foreign Currencies
Paul McCartney’s address to Ukrainians