  The INT/WFC Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS)
is an imaging survey being carried out in H-alpha, r' and i' filters, with the
Wide Field Camera (WFC) on the 2.5-metre Isaac Newton Telescope (INT) to a
depth of r'=20 (10 sigma). The survey is aimed at revealing large scale
structure in our local galaxy, and also the properties of key early and late
populations making up the Milky Way. Mapping emission line objects enables a
particular focus on objects in the young and old stages of stellar evolution
ranging from early T-Tauri stars to late planetary nebulae. In this paper we
present the IPHAS Initial Data Release, primarily a photometric catalogue of
about 200 million unique objects, coupled with associated image data covering
about 1600 square degrees in three passbands. We note how access to the primary
data products has been implemented through use of standard virtual observatory
publishing interfaces. Simple traditional web access is provided to the main
IPHAS photometric catalogue, in addition to a number of common catalogues (such
as 2MASS) which are of immediate relevance. Access through the AstroGrid VO
Desktop opens up the full range of analysis options, and allows full
integration with the wider range of data and services available through the
Virtual Observatory. The IDR represents the largest dataset published primarily
through VO interfaces to date, and so stands as an examplar of the future of
survey data mining. Examples of data access are given, including a
cross-matching of IPHAS photometry with sources in the UKIDSS Galactic Plane
Survey that validates the existing calibration of the best data.
