Where can i find Latitude & Longitude data for the coastlines of the world?

Natural Earth would be the place to go. The data is open source and generalised for use at different scales.

http://naturalearthdata.com/downloads/10m-physical-vectors

Check NOAA's GSHHG (Global Self-consistent, Hierarchical, High-resolution Geography Database).

The database is constantly being updated and maintained (latest update since Im answering this Q: July 1, 2013)

GSHHG is:

a high-resolution geography data set amalgamated from two data bases in the public domain: World Vector Shorelines (WVS) and CIA World Data Bank II (WDBII). The former is our basis for shorelines while the latter is the basis for lakes, although there are instances where differences in coastline representations necessitated adding WDBII islands to GSHHG. The WDBII source also provides all political borders and rivers. GSHHG data have undergone extensive processing and should be free of internal inconsistencies such as erratic points and crossing segments. The shorelines are constructed entirely from hierarchically arranged closed polygons

The data are available in hdf4/3, ESRI Shapefile and binary formats.

http://www.soest.hawaii.edu/pwessel/gshhg/index.html

Check out https://osmdata.openstreetmap.de/ from Jochen Topf. The data has been derived from OpenStreetMap ways tagged with natural=coastline. See also the data update.