Many times when we train, we get waiting tickets. But to check PNR status, there are few websites which are always down. One is http://www.pnrstatusupdate.in
Any more website to check PNR status?
Indian Rail website .If you have booked online through IRCTC website, you can check it through there itself.
A point to remember, if the Indian railways network is down, it doesn't help if you use their site or some other site, as all data update comes from the Indian railways network. Any reason not using the railway's website ?
Get all the information instantly from eRail website, this website is maintained by CRIS (Centre for Railway Information Systems)
The advantage of this site is this doesn't require a Login or a Captcha, its fast and convenient and not only the PNR status but you can check all other information about trains such as train inquiry, seat availability etc.
erail.in extension is available for Chrome/Firefox which will enhance your browsing experience with their website.
http://www.indianrail.gov.in/pnr_Enq.html (No Login, Captcha required)
The website that dumbcoder mentioned is obviously the first place you can go however just to ensure that this question is answered more comprehensively, http://irctc.co.in which is the site you use to book your tickets is another good option. There are also telephone based services which you may use. You can actually call 139 or send an SMS to them as per instructions in http://www.indianrail.gov.in/139.html to get a status update.
As I have answered in another thread erail.in gives you convenience and I have never seen it being down in the last 6-7 years so thats a pretty reliable source (with convenience too).
Simply go to this site - https://www.pnr-status.info/
Why this site best among all pnr status checking site? cause its not just showing confirm ticket pnr status but also showing seat/berth type eg - CNF/D1/7/WS
ws means - Window Seat