Six Ukrainian parties signed an accord to set up the Our Ukraine Viktor Yushchenko Bloc to form a joint election list for the parliamentary elections in 2006. In particular, the bloc includes the People's Union Our Ukraine (NSNU), the People's Movement of Ukraine (NRU), the Party of Industrialists and Entrepreneurs (PPPU), the Congress of Ukrainian Nationalists (KUN), the Christian-Democratic Union (CHDS) and the Ukrainian Republican Party Sobor (URPS).
Source: NSNU

A liberal faction of the social democratic Democratic Party (DS) led by Čedomir Jovanović formed the Liberal Democratic Party (LDP). The party also reached a coalition agreement for the next parliamentary elections with the liberal Civic Alliance of Serbia (GSS).
Sources: RFE/RL & LDP

A leftist wing, led by former Moldovan PM Dumitru Braghis and seven deputies, left the liberal party Alliance Our Moldova (AMN). Braghis accused party leader Serafim Urechean of dictatorial practices in running the party.
Source: RFE/RL

A faction of the Great Romania Party (PRM), led by former vice-president Corneliu Ciontu, formed the new centre right People's Party (PP).
Sources: Wikipedia & PP

The European People’s Party (EPP) approved to give the Democratic Party (PD) of Romania the status of observer. The EPP decided not to accept the application of the Conservative Party (PC) of Romania, as it does not fulfill the EPP criteria.
Source: EPP

An extraordinary PDS session has decided to change the name of the party to The Left Party (THE LEFT). Appending the acronym PDS is possible. This can be decided either at the federal level or by the party organisations in the states.
Source: PDS

The nationalist wing, led by the party's co-leader Sergey Baburin, left the Homeland - National Patriotic Union (NPS). This second split led to a reunification of Dmitry Rogozin's and Sergey Glazyev's supporters within the leftist NPS.
Source: RFE/RL

At the 5th National Congress the party name of the United List of Social Democrats (ZLSD) was shortend to Social Democrats (SD).
Source: ZLSD

The Party of Democratic Socialism (PDS) and a splitter group of left-wing SPD-dissidents, the Labour and Social Justice - The Electoral Alternative (WASG), agreed to form an election alliance for the general elections scheduled in September. After the elections a joint commission is to be set up to discuss all further aspects of the planned unification into one party.
Source: Süddeutsche Zeitung 

A new liberal formation, the Democratic Party (PD), was set up by Freedom Union (UW) leader Władysław Frasyniuk, former PM Tadeusz Mazowiecki and Deputy Prime Minister Jerzy Hausner, former member of the SLD. The Freedom Union (UW) merged into the new PD.
Source: Die Tageszeitung

Freethinking Democratic Party (FDP) and Liberal Party of Switzerland (LPS) intend to build up a federation called Union of Freethinkers and Liberals (UFL).
Source: LPS

The Estonian Centre Party (EK) absorbed the extraparliamentary Estonian Pensioner's Party (EPE).
Source: EK 

Leading members of the FPÖ and most members of the federal parliamentary group left the FPÖ and established a new party called Alliance for the Future of Austria (BZÖ). The BZÖ is led by Jörg Haider, the Prime Minister of Carinthia.
Source: Der Standard

The Hungarian Democratic Forum (MDF) absorbed the small Hungarian Democratic People's Party (MDNP).
Source: Der Standard