As you have asked about the list of Indian companies in information and Technology (IT) sector, I am giving you some information about it, check below fort he details

Tata Consultancy Services
Infosys
Wipro
HCL Technologies
Tech Mahindra
Oracle Financial Services Software
Mindtree
Mphasis
Hexaware Technologies
Tata Elxsi
3i Infotech
ALTEN Calsoft Labs
Accel Frontline
A3logics (I) Pvt. Ltd
Aditi Technologies
Adrenalin eSystems
Aftek
Algoworks
Atom Technologies
BirlaSoft
Blue Star Infotech
C-DAC
CMC Limited
Cognizant
Computer Sciences Corporation
Cybage
Cyient
Cynapse
Datamatics Global Services
Dinclix GroundWorks Global
Eclerx
Experion technologies
Firstsource
Flytxt Mobile Solutions
Fulcrum Worldwide
Geometric Limited
Godrej Infotech Ltd
Happiest Minds Technologies
Harbinger Systems
Honeywell
HSBC GLT India
IGATE
Impetus Technologies
Indusface
Infinite Computer Solutions
InfoBeans
Intellect Design
KPIT Technologies
Larsen & Toubro Infotech
Mastek
Melstar Information Technologies
Microland
Micromax Mobile
Microsoft India PL
Mindfire Solutions
Mindteck
Mistral Solutions
MobME
Monsoon Multimedia
Nihilent
NIIT Technologies
Nucleus Software Exports Ltd.
NVISH
Ocimum Bio Solutions
Onward Technologies
Persistent Systems
Plivo
Polaris Financial Technology Limited
Pramati Technologies
Quest Global
R Systems Ltd
Ramco Systems
Rediff.com
Rolta India Ltd
Samsung India Software Center
Sankalp Semiconductor
Sasken
Sonata Software
SPAN Infotech (India) Pvt. Ltd.
SunTec Business Solutions
Tata Interactive Systems
Tejas Networks
ThinkPalm Technologies
Thirdware
Thoughtworks
Trigent Software
UST Global
Walkover Web Solutions
WNS Global Services
Xansa
Xerox
Zensar Technologies
ZOHO Corporation