What would be the best way in Python to determine whether a directory is writeable for the user executing the script? Since this will likely involve using the os module I should mention I'm running it under a *nix environment.
Although what Christophe suggested is a more Pythonic solution, the os module does have the os.access function to check access:
os.access('/path/to/folder', os.W_OK)
# W_OK is for writing, R_OK for reading, etc.