A couple of free ones can be found below.

http://www.adobe.com/products/acrobat/readstep2.html (Adobe Reader)

http://www.foxitsoftware.com/pdf/rd_intro.php (Foxit Reader)

To find a datasheet, you first need to find some info on the part. Luckily, they have part numbers which can be used to help identify them. They may also have the manufacturers logo on them. Finding the manufacturer can be extremely useful as the most up-to-date information is usually available on their website. For help in finding the manufacturer based on their logo, check out the following sites. They also include links to the manufacturer’s websites. Datasheets can normally be found under the support/download section, or you can put the part number in their search bar.

http://www.classiccmp.org/rtellason/logos/semiconductorlogos.html

http://www.dialelec.com/semiconductorlogos.html

http://freespace.virgin.net/matt.waite/resource/logos/index.htm

http://hallaweb.jlab.org/tech/jackjack/public_html/manuals/chip_specs/Manufacturers%20of%20ICs%20and%20their%20logos%20-%202.htm

http://www.chipdocs.com/logos/logotypes.html?ReR=GG&ReR=GG

If you can’t find any information on the manufacturer, or are unable to find a datasheet on their website, you do have a few more options. There are several search engines on the web to help locate datasheets. Some free ones are listed below. You can search by part number, or even by a partial part number.

http://sdw.bgs.nu/a.html

http://www.datasheetcatalog.com/

http://www.alldatasheet.com/

http://www.datasheetarchive.com/

If those fail, you can try using a search engine such as google. Adding “pdf” to your search string can slim down the results, reducing the amount of sites just selling the part with no other useful information. There is also a chance of finding no information on a particular part. Some manufacturers will produce special order parts with “house” numbers, which can mean nothing except to the company that actually purchased them