Florina in northern Greece is a useful staging post from the Republic of Macedonia into Greece. (While in Greece, to avoid hostility, you may do best to refer to the non-Greek part of Macedonia as "Skopje" or just say the name of the town you have travelled from, as the use of the name "Macedonia" to describe a Slavic country is a sensitive subject for Greeks.)
The weather in Florina is quite unstable during the whole season, especially during the winter. Florina is the city with the most snowfalls of all Greece that lasts from December to March. During the winter, the most of the time, the temperature is below zero degrees of Celsius, so be prepared.
There are frequent buses. Valid information can be found on  (Update: 14/01/2012)
From Bitola it is about 30 km, and takes a little over an hour by taxi. Taxi drivers from the Republic of Macedonia require a special permit to operate in Greece, and they might use this fact to quote you a fare of up to €40. You should be able to knock them down to €25 or less. If they don't have a permit, they might offer to take you to the border for just a few euros, but you then have to walk between the border posts (800m) and hope to find a Greek taxi. Alternatively, they might take you all the way but pretend that they are a private car once in Greece.
You can easily get around by foot. It is a nice way to see beautiful neoclassical houses and explore the city of Florina.
First of all, see the city of Florina. The way that the old and the new city are split by Sakouleva river is unique.
Also, make a visit at Nimphaio village, where you can find the Αrcturos organisation.
If you visit Florina during winter, you should also pay a visit at the ski resort (Vigla) which is near the town (20 minutes by car). It has very nice slopes to try if you like skiing or snowboarding, have a ride with a snowmobile or you can just have a coffee at the chalet near the slopes. The prices are 12 euros during weekdays and 15 euros during weekend for the daily pass and you can rent the equipment you need.
The most famous event of the city is the fires that the citizens start on the streets of the city during Christmas Eve (at midnight of the 23rd of December).
The most famous product of Florina are the big red peppers (Florinis) which are in most cases sweet and in rare cases a little bit spicy. The most common ways to taste them are roasted, blended with tomato as a sauce, staffed with feta cheese or staffed with minced meat and rise (gemista).
Also Florina has a good variety of sweets and the most famous is karidato.
You can also find one of the best, if not the best, variety of beans coming from the villages around Prespes lakes (called Prespon king bean or fasolia gigantes Prespon).
Probably, you can also find Carp fish (Grivadi) from Prespes, but I believe that you should try it on a restaurant by the lake at Prespes.
As a street food, Florina has to offer you big sandwiches called Glossa. You are going to find a variety of ingredients to staff the sandwiches.
You shoud try sour water (ksino nero) which is natural sparkling water from the village of Florina called Ksino nero. You can also try a very good variety o refreshments with fresh juice and sour water such as orangeade, lemonade, gazoza (lime), sour Cherry, soda water, cola, strawberry, kiwi, rokino (mixed fruit), apple, gazoza (pear) and tonik water.
You can also try a wide variety of wines produced at a village near Florina called Amyntaio. The most common variety is xinomavro.