Attached are two services written to take advantage of Snow Leopard's context menu/automator integration.
TxtToTM sends text selected in any application and opens a new TextMate window with that text inserted. There is a rudimentary heuristic set up to check if the text is Javascript/HTML/CSS/Applescript and set the textmate bundle type accordingly. This is implemented through an Applescript in Automator. So this can be extended/improved/hacked by the many textmate users who are, no doubt, more proficient in Applescript than me.
Edit in Textmate will open any file or folder selected in Finder in Textmate. Folders open to Projects. These services show up when contextually appropriate (i.e. when you have text selected it will be in your right click menu).
To install unzip, and put the two files in ~/Library/Services. You may need to go to System Preferences/Keyboard/Services and make sure the box next to each of them is checked for them to show up in your context menu.
These are written using Automator's new Create Service function in Snow Leopard, so are 64 bit compatible. I have no idea if they would work in 10.5.