If you are given the task to hire a speaker, here are the things that you need to know before finalizing the contract
Fees: Is it going to be an international event, with orators from various countries? If yes, you need to ask and clarify the amount of fees they would be charging. Better still, ask the speakers to quote their fees in the USD.
You will need to clarify if the fees are inclusive of the travel expenses, and other ancillary expenses. Are your guests flying by first class, business or economy? If you have a written policy, you need to share it with them, before you hire a speaker.
Each country has its own set of rules regarding to the baggage, clearance, allowable items, etc. You should send the guideline to the speaker, so he knows what is to be expected.
If there are products to be displayed, please check with the Customs department, if the said product is allowed in the country hosting the event. Check if there is any duty on the product, and the percentage of the duty.
Check out the visa regulations. You may need to arrange for the visas, and if so, make sure that you do it well ahead of the travel date.
Your speaker may be coming from a different time zone. Check out the time difference before you hire him, so as to give him enough time to rest and prepare for the event. Also, you will have to get the hotel bookings done accordingly.
Give adequate information about the event, your organization, and the general direction or the points that you would want them to cover in the speech. If you need to send materials about your company to the speaker, make sure you send them well in advance so that they have enough time for preparations.
Give an itinerary to the program well in advance. If you are going to have a dress code at the event, spell it out clearly to them.
If there are any special instructions regarding the country of travel, it should be clearly spelled out. For example, if the venue is in one of the conservative countries, then you need to tell the guests not to pass a religious comment or an offensive comment.
In short, you will need to check out on all the issues before you hire a speaker and make your event a grand success.