Al-jawab billahi at-taufeeq (the answer with Allah's guidance)
1) The payment of Zakat is compulsory on the excess wealth or effects which is equal to/or exceeds the value of Nisab, and which is possessed for a full Islamic year.
The rate of Zakat is 2.5%.
* It should be noted that the value of Nisab is according to the cost of silver and gold. At present silver is �354.26 and gold is �2358.75 approx. on 04/02/11, however, this is subject to change.
2) You can pay your Zakat money to the collectors of Zakat like, Masjids confirming that they will act as a representitive to give to the poor and not to give it direct, or it can be given directly to the poor without the means of a Masjid.