Basic was never a language that was used by mainstream developers for the 770 or later devices. Common language are "C", "Python", and to some extent "C++".

Most developers build applications based on "frameworks" or "graphical toolkits". These are large collections of code written in one of the languages above that attempt to simplify creating complex programs by having already written code to do common tasks such as creating a window or opening a file. In practice this amounts to giving you bricks to build a building instead of having to make the bricks yourself. You still need to lay out the bricks yourself.

On the 770, N800, N810 and N810WE, the most common framework was Hildon itself an extension of gtk+.

Starting with the N800 the "Qt" framework (based on C++) became available, on the N900 it became standard and on the N9 it is the only framework although work is ongoing to bring gtk to the N9 as well .

Most developers don't recommend doing the actual programming on the device itself they use something called scratchbox (which is available for building applications for the 770) or Qt Creator, which is not. Code is then compiled for the device (in the case of C and C++) and then copied to the device (all languages).

Nokia created scripts to help make installing scratchbox easier. Your Mileage May Vary on whether this helps or not.

To maximize the ease of installation code is usually bundled into one or more deb files , although this is often where developers get stuck. If you do create a deb and you are developing for the N800 or later you can then learn to upload your new application to extras, Unfortunately uploading to the version of extras for the 770 has been closed mostly due to inactivity and the resources required. You can still download but not upload. Uploading N800 applications is still possible and in some ways quicker than the process for the N900. the concept of extras for the N9 is still in flux

Having said ALL THAT, if you really want to, it appears you can download a version of SmallBasic from here straight to your 770. You may or may not get the ability to create a program that has a graphical interface but this page implies that you can get something. If you're used to programming on calculators you might feel comfortable with the limitations.

Note, the amount of help you can expect to receive is directly proportional to the likelihood your device was available to be bought new in 2010. In other words expect no help in developing for the 770 (in fact many of the help guides for the 770 were taken down from this website as they confused developers of later devices), you can expect a little help if you're developing for the N8X0's, some help for the N900 (it used to be a lot more but many developers have left) and back to down to little help for the N9 (as that device is not available for many people and what help there is often has been siphoned away to other websites see meego)

Programming for the 770 and later devices is not particularly friendly, especially for developers brand new to programming in a linux environment, which is why people keep asking you to ask more specific questions other than "how do I program for the 770?"

In general, install a couple of apps on the 770 before you start to develop for it, to get a sense of how applications normally look, feel, and act. Next read everything in this website's wiki, read many of the "stickied" threads on talk.maemo.org, after that try out a hello world program or two, and then finally if you're still convinced you want to, try to develop an application.

If you do, you may be the next great Developer!