There are a numerous sites where you can read and search through the Quran. My most frequented one is the one hosted by Al-Islam.org. However, quite often when I’m offline and I want to search through the Quran, the only viable alternative was to peer through index of the physical book itslef to find the verse I’m looking for. So using Dinesh’s help at office, we’ve put together Quran in pdf format. The file is a mere 4.6 mb in size and enables you to search through the translation quite easily without being connected to the internet. This pdf copy of the Quran can be downloaded from here. Cheerio.
If you need the same for Arabic, “al-Mu’jam al-mufahras lilfaz al-Qur’an” is helpful, took me forever to find something like this. I just bought it in book form, very helpful, here it is in web form: http://www.qurancomplex.org/IdIndex/default.asp?harf=1&job=wordlist&l=arb