In addition to the links provided by Ismail, you may also download LiDAR data from following sources:

1) USGS Earth Explorer:

http://earthexplorer.usgs.gov/

2) United States Wiki - National LiDAR dataset:

https://en.wikipedia.org/wiki/National_Lidar_Dataset_(United_States)

3) National Ecology Observatory Network (NEON)

http://www.neonscience.org/data-resources/get-data

As far as software is concerned, it depends on the intended application and also matter of choice. Some suggested software for LiDAR processing are:

1) FUSION/LDV

http://forsys.cfr.washington.edu/fusion/fusionlatest.html

2) SAGA-GIS

http://www.saga-gis.org/en/index.html

You may also use ArcGIS, ENVI and GRASS-GIS for LiDAR data processing.

Hope this helps.

Thanks To every one for sharing information.

About the software,

FREEWARE

-You can use FugroViewer, available at

http://www.fugroviewer.com/

-Or an extension from an older version of gvSIG, named DIELMO.

-Lastools as a complement of QGIS

Lastools, available at http://www.cs.unc.edu/~isenburg/lastools/download/

QGIS, at http://qgis.org/es/site/forusers/download.html

COMMERCIAL SOFTWARE

-GlobalMapper (2-weeks trial license)

http://www.bluemarblegeo.com/products/global-mapper-download.php

-ArcGIS

http://www.esri.com/software/arcgis/arcgis-for-desktop/

About the data, you can access to Spanish data (.laz format, 2x2 km) at the Centro de Descargas (Instituto Geográfico Nacional) Website:

http://centrodedescargas.cnig.es/CentroDescargas/buscadorCatalogo.do?codFamilia=LIDAR

Good luck

Thanks

There are many options for lidar data processing and analyses. One of them is the combination of Fusion (http://forsys.cfr.washington.edu/fusion/fusionlatest.html) and ArGis.  

You can also try LiDAR360. It  has the ability to visualize large point cloud data and automatically align flight strips, classify points and generate spatial products. It also contains tools for forest  and  powerline application. 

(http://greenvalleyintl.com/product/lidar360/)

Try out for multiple possibilities http://spatial-analyst.net/book/system/files/Hengl_2009_GEOSTATe2c0w.pdf

Hi there,

consider using CloudCompare to visualize, edit and process 3D point clouds, as well!

If you use the ArcGIS Software you can download the free software LAStools, you will obtain a very good results.

Dear Prafulla,

you can also consider computree .......