I did not understand your question clearly.
1) If u have dual booting system with NTFS and Linux file system then to write to ext3 from within Windows u can use a software like Paragon Mount Everything or :
http://uranus.it.swin.edu.au/~jn/linux/ext2ifs.htm
2) If u have seperate Window and Linux machines and if u want to read/write to Linux computer over the network than use SAMBA, FTP, WinSCP(WinSSHD) etc.