Travel information for Cambodia is easy to find and if you are going to Cambodia and there is a world of information on the internet, however, there is one web site which has some of the most comprehensive and detailed information which includes the land border crossings with all neighboring countries, very detailed information on how to make land border crossings into and out of Cambodia. The web site also has excellent maps of the different regions and main tourist places such as Siem Reap and Sihanoukville and other locations as we as information on visas, an excellent listing of accommodations which are not on any booking engine such as HostelWorld or HostelBooker and others.
Canby Publications - This is my "bible" for Cambodia. It is probably one of the best overall web sites I have seen for overall comprehensive information on any country. When I go there, the first place I check is this web site. When viewing this web site, look to the left hand portion of the main page where all the links are located. The right hand side are links to other sites such as hotels which may be of interest, but if you are looking for the information on how to get there overland, maps and all the good information then the links are on the left side of the page.
Also, there are many different ways to obtain your 30 day tourist visa. As of October 1, 2014 the new government increased the tourist visa fees. Some decide to get these at the border crossing which now cost $30 US dollars but one of the issues with doing this is the potential for being taken advantage of by the locals or border/immigration officials if you are not prepared and know what is going on. One of which is the "official health check" desk which will ask for 20 Thai Baht, it is not required to pay this. Also, if you arrive without a photo for your visa application expect to be asked for 200 Baht but try to refuse paying or bargaining. Your skills and attitude at the time will decide how much you pay in this event.
Since Cambodia wants to be a tourist friendly country, you can make an online visa application and pay by credit card for a 30 day tourist visa. This process is very easy and I use it for every time I go into Cambodia. Just take this link Cambodia Ministry of Foreign Affairs, look on the main page for "apply for e-visa" and click that link. You will be taken to the application page for the visa. You will need a photo to upload which is a JPG format, the format of the image is called a bust shot meaning shoulders and head, has a white background and its size should be no larger than 1.5 inches wide x 1.6 inches tall or 3.81cm wide x 4.2 tall. Effective October 1, 2014 the new visa costs for the e-visa will be $30 US dollars + a $7 UD dollar processing fee. A note of caution, there are a number of fake web sites that pretend to be the official E-Visa application web sites of the Cambodian government, do not be fooled, use the link supplied in this post and you will have the correct web site.
Once you complete the application and payment process you will receive two emails, one is a payment receipt the other email will have a link you will take three days later to acquire the actual e-visa which will be emailed to you. ***NOTE*** During the application phase after you make your payment a screen will appear with a button that says "print receipt", you must print this out and keep because the transaction number will be needed to check the status of the application. If for some reason you do not have a printer then at least write the transaction number down for your records. The transaction number on the "receipt" which is emailed to you is not, I repeat, not the transaction number you will use for application checking and changes if needed.***** When the e-visa has been approved you will receive an email with a PDF document attachment which is the e-visa. Open this PDF document and follow the instruction as shown.
Before you make the e-visa application, I suggest that you read the web site as it will show the ports of entry and exit which the e-visa will be accepted and this could be very critical if you get this type of visa and try to enter Cambodia at a border crossing point where the e-visa is not accepted.
If you decide to use this service you will find it very easy and the only problem you could face is that their web site may not be responding which does occur from time to time, so make your application early enough to allow for this issue.
Travel Safe, Travel Happy.