Try posting few good clear pictures first

They won't be fresh by the time they get much past your local post office!

Your best bet is to take samples along to your nearest botanical gardens (by pre-arrangement). There are literally hundreds of mint species, and many more cultivars. Things become more complicated because mints hybridise easily. It's virtually impossible to identify one of these just by looking at it or smelling it. Chemical analysis is needed - and a professional expertise in biology comes in very handy as well.

Still, if you can post photos, some of us here might be able to narrow it down a little bit for you. For instance, peppermint has a dark green colour, more pointy (lanceolate) leaves - and many of its derivatives have those characteristics. Spearmint (and many of its derivatives) is a paler green, the leaves are more rounded. Apple Mint often has a furry leaf, and some varieties are variegated (have at least 2 colours, or shades of colours). There's a variegated Apple Mint known as Pineapple Mint in America.

I'll complicate matters for you even further by mentioning that common or local names might include the word 'mint' when the plant the name refers to isn't a mint at all! (A true mint will have the name Mentha Something.)

Three examples of this are Asian (Vietnamese) Mint
http://en.wikipedia.org/wiki/Persicaria_odorata

and Mexican Marigold Mint (Tagetes lucida) - which I know as Winter Tarragon, but it has numerous other names as well, depending on where you come from - and it's neither a tarragon nor a mint!!

and Horsemint, which is a member of the mint family in England (Mentha longifolia); but in America, it's any member of the Monarda (bergamot) family!

Check out the images at this URL, and browse through the websites they came from.

http://images.google.com.au/images?hl=en&client=firefox-a&rls=org.mozilla:en-GB:official&channel=s&q=mint+species&oq=&um=1&ie=UTF-8&ei=Rn2QS6vYAZCTkAX93oGODQ&sa=X&oi=image_result_group&ct=title&resnum=4&ved=0CCgQsAQwAw

Here is a link that might be useful: types of mint

While I'm unfamiliar with the specifics for any given nation, many if not all countries have regulations about shipping live materials across their borders. Most of the regulations try to minimize the spread of disease and pests from one location to another. Some locales, like the state of California, have even more stringent regulations than the national norm. Given that, I would not suggest shipping plant materials internationally.

I agree with Daisy. Try to find someone local to ID or post some pictures. We'd be happy to try to ID from photos. Use a free photo service like Picasa or Photobucket to post photos of decent resolution and size to aid with ID'ing.

FataMorgana