According to Space.com (www.space.com):

MOSCOW (AP) – Russian space officials Monday set a Nov. 9 blastoff for a European probe to explore Venus after its earlier launch was postponed because of a booster rocket problem.
Engineers will be able to fix the flaws by that date, the Federal Space Agency said in scheduling the launch at the Russian-leased Baikonur Cosmodrome in Kazakhstan.

SpaceDaily.com (www.spacedaily.com) gives a nice overview of all the previous space missions to Venus:

1961: Venera 1 (Venus 1), Soviet-made probe designed for a fly-by of Venus. Fate unknown. Communications with ground station broke down about seven million kilometers (4.37 million miles) from Earth.

1962: Mariner 1 and Mariner 2 (US). Mariner 1 veered off-course and had to be destroyed shortly after launch. Mariner 2 became the first successful interplanetary probe. Found no significant magnetic fields or radiation belts around Venus. Heat sensors found the surface to be dry and scorching hot.

1965-83: Venera 2 - Venera 16. Ambitious programme of Soviet campaign of fly-bys and landings, characterised by several failures but some successes. Among them: Venera 7 (1970), which parachuted a capsule of scientific instruments to the surface, marking the first successful landing on Venus, and Venera 9 (1975), which sent back the first TV pictures of the Venusian surface.

1967: Mariner 5 (US). Flyby, measuring magnetic fields, charged particles, ultra-violet emissions.

1973: Mariner 10 (US). NASA flyby of a probe en route for Mercury. Returned first close up pictures of Venus, despite navigational problems.

1978: Pioneer Venus (US). Orbiter, operated until 1992. Included the Pioneer Venus Multiprobe (US). Comprised one large and three small probes, equipped with sensors, that were sent down to the surface in 1978.

1984: Vega 1 and 2 (Soviet). Flybys of Venus while en route to Halley's Comet, dropped scientific packages to surface.

1989: Magellan (US). Orbiter designed to map Venus' surface. Highly successful. Operated until 1994.

- Galileo (US). Flyby of Venus in 1990 while en route to the outer planets.
2004: Messenger (US). Two scheduled fly-bys of Venus (Oct 2006, June 2007) en route to Mercury.

Venus is a harsh place to visit: sulphuric acid clouds and 800 degree F. surface temperatures.