1. http://www.webteam.iitkgp.ernet.in/academic/minorsubjects2.php?BranchCode=BTEE3
2. http://entrance-exam.net/forum/general-discussion/best-books-prepare-gate-instrumentation-engineering-274609.html

3. http://instrumentationgate.blogspot.in/
4. E-BOOKS DOWNLOAD http://r4k35h.blogspot.in/2010/07/ebooks-for-ece.html

5 http://www.learnerstv.com/Free-Engineering-Video-lectures-ltv146-Page1.htm
6 http://freevideolectures.com/Course/2347/Industrial-Instrumentation

7 Nptel http://nptel.iitm.ac.in/courses.php?disciplineId=106

for previous year papers http://gate.iitm.ac.in/

suggestion from previous Gate topper Manish Tiwari Gate 2011 RANK 4

http://forum.gatecounsellor.com/viewtopic.php?f=77&t=303

USEFUL FORUM http://forum.gatecounsellor.com/viewforum.php?f=37

http://www.gatecounsellor.com/Apply_IN.php
CHECK WHERE CAN YOU APPLY WITH YOUR IN PAPER SCORE

Books

http://forum.gatecounsellor.com/viewtopic.php?f=77&t=303

Tips from Gate 2012 AIR 86
http://gyancentral.com/articles/post-graduate/engineering/post-graduate-engineering-entrance-exams/gate-2012:-the-top-1-percent-share-their-preparation-strategy-and-future-plans

some materials
https://rapidshare.com/#!download|386p2|286233037|
GATE.Instrumentation.Study.Material.zip|19679|0|0 (copy paste it)

http://www.filestube.com/1b93837864eeeff503ea,g/GATE-Instrumentation-Study-Material.html

syllabus
http://gatesyllabus.blogspot.in/2007/04/2007-syllabus.html

Linkedin profile of Topper Manish Tiwari AIR 4 2011
http://in.linkedin.com/pub/manish-tiwari/44/898/90a

http://cedt-gate.blogspot.in/