Transfer emails from Thunderbird on PC to  Asus Transformer email app is there any way how can I get my e-mail from Thunderbird on my W7 pc to Transformer? My laptop just died so I am considering Transformer, but without my mails...

Syncing via GMail isnt a solution for me, because I have multiple e-mail accounts on many servers with both POP3 and IMAP.
If your goal is solely to transfer your email, your best bet would be to create a dummy gmail account with IMAP and add it to tbird as a separate account (so that it doesn't go to the general inbox).  Once you had that done, in tbird copy all the folders you want transferred to the dummy account and wait for it to sync with gmail's IMAP server.  Finally, add the dummy gmail account to your choice of email client on your phone and wait for the IMAP sync to complete.

If you want to continue to receive email on your phone from all these accounts, you can add them in as you like to the email client of your choice.  Personally I'd recommend K9 for multiple email account management myself; it has an unified inbox similar to tbird's general inbox and is all around mucho handy.