aspell is the spell checker replacement for ispell. It can be called by vim to check your texts.
First, you have to save the file (:w).
The command to call is the following:
:!aspell -c %where % will be remplaced by the name of the file being edited. If your text is in UTF-8, specify it with:
:!aspell -c % --encoding=utf-8
You can add the following line to you .vimrc. Then the key F3 will call the speller in UTF-8 mode.
:w! :!aspell -c % --encoding=utf-8 :e! %