The president of Pakistan is elected in a secret ballot by the two chambers of the national parliament (the National Assembly and Senate) and the four provincial assemblies.
In total, 1,170 people are eligible to vote. But not all votes are of equal weight.
Each of the four provincial assemblies has a total of 65 votes even though only one of them, Balochistan, actually has 65 deputies. This is so that each provincial assembly has an equal say in the election.
North West Frontier Province (NWFP) has nearly double that number of deputies, 124. So, under a formula to weight their votes, roughly two votes cast in NWFP for the same candidate will be counted as one actual vote.
There are five candidates in the running for the presidency: General Pervez Musharraf, Faryal Talpur, Mohammedmian Soomro, Makhdoom Mohammad Amin Faheem and Wajihuddin Ahmed.
The graphic below indicates how much support Gen Musharraf has in the parliament and assemblies.
More than 170 opposition members have resigned from the different assemblies in an attempt to discredit the election.
The National Assembly includes 60 seats reserved for women and 10 seats reserved for Non-Muslims.
The Senate includes 17 seats reserved for women and 17 seats reserved for technocrats and Muslim clergy.
The Members of the National Assembly are elected for a term of five years whereas the Members of the Senate are elected for a term of six years, with staggered elections every 3 years.